Indication of information in channel state information (CSI) reports

Abstract

Wireless communications systems and methods related to CSI feedback are provided. A user equipment (UE) receives an indication of a restricted set of frequency domain (FD) beamforming components and one or more channel state information reference signals (CSI-RSs). The UE can transmit a channel state information (CSI) report indicating a plurality of precoding coefficients based on the received one or more CSI-RSs and the restricted set of FD beamforming components.

Description

Technical Field

[0001] The techniques discussed below generally relate to wireless communication systems, and more particularly to Channel State Information (CSI) reporting operations. Certain embodiments can enable and provide techniques that allow communication devices (e.g., user equipment equipment or base stations) to efficiently convey Channel State Information (CSI) feedback (e.g., with minimal overhead).

[0002] introduction

[0003] Wireless communication systems are widely deployed to provide various types of communication content, such as voice, video, packet data, message sending and receiving, broadcasting, and so on. These systems can support communication with multiple users by sharing available system resources (e.g., time, frequency, and power). Wireless multiple access communication systems may include several base stations (BSs), each supporting communication from multiple communication devices simultaneously, which may also be referred to as user equipment (UEs).

[0004] To meet the growing demand for extended mobile broadband connectivity, wireless communication technologies are evolving from Long Term Evolution (LTE) to Next Generation New Radio (NR), often referred to as fifth generation (5G). For example, NR is designed to offer lower latency, higher bandwidth or throughput, and greater reliability compared to LTE. NR is designed to operate across a wide range of frequency bands, from low-frequency bands below approximately 1 GHz and mid-frequency bands from approximately 1 GHz to approximately 6 GHz, to high-frequency bands such as millimeter wave (mmWave) bands. NR is also designed to operate across different spectrum types, from licensed spectrum to unlicensed and shared spectrum. Spectrum sharing allows operators to opportunistically pool spectrum to dynamically support high-bandwidth services. Spectrum sharing can extend the benefits of NR technology to operating entities that may not have access to licensed spectrum.

[0005] Channel State Information (CSI) provides a mechanism for the UE to measure the quality of the radio channel and report it back to the base station (BS). The BS can transmit CSI-RS (reference signal) to the UE, and the UE can measure the CSI information and feed it back to the BS, so that the transmitted data can be pre-coded according to the channel characteristics to better transmit data between the BS and the UE.

[0006] A brief overview of some examples

[0007] The following outlines some aspects of this disclosure to provide a basic understanding of the techniques discussed. This overview is not an exhaustive summary of all conceived features of this disclosure, and is neither intended to identify all key or decisive elements of all aspects of this disclosure, nor to define the scope of any or all aspects of this disclosure. Its sole purpose is to provide, in an overview form, some concepts of one or more aspects of this disclosure as a prelude to the more detailed description that follows.

[0008] In one aspect of this disclosure, a wireless communication method includes: receiving from a base station (BS) an indication of a restricted set of frequency domain (FD) beamforming components by a user equipment (UE); receiving from the BS one or more channel state information reference signals (CSI-RS) by the UE; and transmitting to the BS a channel state information (CSI) report indicating a plurality of precoding coefficients based on the received one or more CSI-RS and the restricted set of the FD beamforming components.

[0009] In an additional aspect of this disclosure, a wireless communication method includes: a user equipment (UE) receiving from a base station (BS) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; the UE receiving one or more CSI-RS from the BS; and the UE transmitting a Channel State Information (CSI) report indicating a plurality of precoding coefficients to the BS based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0010] In an additional aspect of this disclosure, an apparatus includes a transceiver configured to: receive from a base station (BS) an indication of a restricted set of frequency domain (FD) beamforming components by a user equipment (UE); receive from the BS one or more channel state information reference signals (CSI-RS) by the UE; and transmit to the BS a channel state information (CSI) report indicating a plurality of precoding coefficients based on the received one or more CSI-RS and the restricted set of the FD beamforming components.

[0011] In an additional aspect of this disclosure, an apparatus includes a transceiver configured to: receive from a base station (BS) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; receive one or more Channel State Information Reference Signals (CSI-RS) from the BS by the UE; and transmit from the UE a Channel State Information (CSI) report indicating a plurality of precoding coefficients to the BS based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0012] In an additional aspect of this disclosure, a computer-readable medium having program code recorded thereon includes: code for enabling a user equipment (UE) to receive from a base station (BS) an indication of a restricted set of frequency domain (FD) beamforming components; code for enabling the UE to receive one or more channel state information reference signals (CSI-RS) from the BS; and code for enabling the UE to transmit a channel state information (CSI) report indicating a plurality of precoding coefficients to the BS based on the received one or more CSI-RS and the restricted set of the FD beamforming components.

[0013] In an additional aspect of this disclosure, a computer-readable medium having program code recorded thereon includes: code for causing the user equipment (UE) to receive from a base station (BS) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; code for causing the UE to receive one or more Channel State Information Reference Signals (CSI-RS) from the BS; and code for causing the UE to transmit a Channel State Information (CSI) report indicating a plurality of precoding coefficients to the BS based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0014] In an additional aspect of this disclosure, an apparatus includes means for receiving from a base station (BS) an indication of a restricted set of frequency domain (FD) beamforming components; means for receiving one or more channel state information reference signals (CSI-RS) from the BS; and means for transmitting to the BS a channel state information (CSI) report indicating a plurality of precoding coefficients based on the received one or more CSI-RS and the restricted set of the FD beamforming components.

[0015] In an additional aspect of this disclosure, an apparatus includes means for receiving from a base station (BS) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; means for receiving one or more Channel State Information Reference Signals (CSI-RS) from the BS; and means for transmitting a Channel State Information (CSI) report indicating a plurality of precoding coefficients to the BS based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0016] In one aspect of this disclosure, a wireless communication method includes: transmitting from a base station (BS) to a user equipment (UE) an indication of a restricted set of frequency domain (FD) beamforming components; transmitting from the BS to the UE one or more channel state information reference signals (CSI-RS); and receiving from the UE a channel state information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS and the restricted set of the FD beamforming components.

[0017] In an additional aspect of this disclosure, a wireless communication method includes: transmitting from a base station (BS) to a user equipment (UE) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; transmitting one or more CSI-RS signals from the BS to the UE using the one or more CSI-RS port groups; and receiving from the UE a channel state information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS signals and the one or more CSI-RS port groups.

[0018] In an additional aspect of this disclosure, an apparatus includes a transceiver configured to: transmit from a base station (BS) to a user equipment (UE) an indication of a restricted set of frequency domain (FD) beamforming components; transmit from the BS to the UE one or more channel state information reference signals (CSI-RS); and receive from the UE a channel state information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS and the restricted set of the FD beamforming components.

[0019] In an additional aspect of this disclosure, an apparatus includes a transceiver configured to: transmit from a base station (BS) to a user equipment (UE) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; transmit one or more CSI-RS signals from the BS to the UE using the one or more CSI-RS port groups; and receive from the UE a Channel State Information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS signals and the one or more CSI-RS port groups.

[0020] In an additional aspect of this disclosure, a computer-readable medium having program code recorded thereon includes: code for causing a base station (BS) to transmit to a user equipment (UE) an indication of a restricted set of frequency domain (FD) beamforming components; code for causing the BS to transmit one or more channel state information reference signals (CSI-RS) to the UE; and code for causing the BS to receive from the UE a channel state information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS and the restricted set of the FD beamforming components.

[0021] In an additional aspect of this disclosure, a computer-readable medium having program code recorded thereon includes: code for causing a base station (BS) to transmit to a user equipment (UE) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; code for causing the BS to transmit one or more CSI-RS to the UE using the one or more CSI-RS port groups; and code for causing the BS to receive from the UE a channel state information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS and the one or more CSI-RS port groups.

[0022] In an additional aspect of this disclosure, an apparatus includes means for transmitting to a user equipment (UE) an indication of a restricted set of frequency domain (FD) beamforming components; means for transmitting one or more channel state information reference signals (CSI-RS) to the UE; and means for receiving from the UE a channel state information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS and the restricted set of the FD beamforming components.

[0023] In an additional aspect of this disclosure, an apparatus includes means for transmitting to a user equipment (UE) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming; means for transmitting one or more CSI-RS to the UE using the one or more CSI-RS port groups; and means for receiving from the UE a channel state information (CSI) report indicating a plurality of precoding coefficients based on the transmitted one or more CSI-RS and the one or more CSI-RS port groups.

[0024] Other aspects, features, and embodiments will become apparent to those skilled in the art after reading the following description of specific exemplary embodiments in conjunction with the accompanying drawings. Although features may be discussed hereinafter with reference to certain embodiments and drawings, all embodiments may include one or more of the advantageous features discussed herein. In other words, while one or more embodiments may be discussed having certain advantageous features, one or more such features may also be used according to the various embodiments discussed herein. Similarly, although exemplary embodiments may be discussed hereinafter as embodiments of devices, systems, or methods, it should be understood that such exemplary embodiments may be implemented in various devices, systems, and methods. Brief description of the attached diagram

[0026] Figure 1 The present disclosure describes one or more aspects of a wireless communication network.

[0027] Figure 2 The present disclosure describes a wireless communication network that implements Channel State Information (CSI) reporting in accordance with one or more aspects thereof.

[0028] Figures 3A-3C This is a diagram illustrating various communication schemes for indicating a restricted set of frequency domain (FD) beamforming components of one or more layers, according to one or more aspects of this disclosure.

[0029] Figure 4 This is a signaling diagram illustrating a method for reporting CSI data associated with FD compression feedback according to one or more aspects of this disclosure.

[0030] Figure 5 This is a signaling diagram illustrating a method for reporting a CSI report associated with a port selection codebook having spatial frequency beamforming, according to one or more aspects of this disclosure.

[0031] Figure 6 This is a signaling diagram illustrating a method for interpreting a CSI report associated with a Channel State Information-Reference Signal (CSI-RS) port having spatial frequency beamforming, according to one or more aspects of this disclosure.

[0032] Figure 7 It is a block diagram of a user equipment (UE) according to one or more aspects of this disclosure.

[0033] Figure 8 This is a block diagram of a base station (BS) according to one or more aspects of this disclosure.

[0034] Figure 9 This is a flowchart of a wireless communication method according to one or more aspects of this disclosure.

[0035] Figure 10This is a flowchart of a wireless communication method according to one or more aspects of this disclosure.

[0036] Figure 11 This is a flowchart of a wireless communication method according to one or more aspects of this disclosure.

[0037] Figure 12 This is a flowchart of a wireless communication method according to one or more aspects of this disclosure.

[0038] Detailed description

[0039] The detailed description that follows, taken in conjunction with the accompanying drawings, is intended as a description of various configurations and is not intended to represent the only configuration in which the concepts described herein can be practiced. This detailed description includes specific details to provide a thorough understanding of the various concepts. However, it will be apparent to those skilled in the art that these concepts can be practiced without these specific details. In some instances, well-known structures and components are shown in block diagram form to avoid obscuring such concepts.

[0040] This disclosure generally relates to wireless communication systems (also known as wireless communication networks). In various embodiments, technologies and apparatus can be used in wireless communication networks such as Code Division Multiple Access (CDMA) networks, Time Division Multiple Access (TDMA) networks, Frequency Division Multiple Access (FDMA) networks, Orthogonal FDMA (OFDMA) networks, Single Carrier FDMA (SC-FDMA) networks, LTE networks, Global System for Mobile Communications (GSM) networks, 5G or New Radio (NR) networks, and other communication networks. As described herein, the terms "network" and "system" may be used interchangeably.

[0041] OFDMA networks can implement radio technologies such as Evolved UTRA (E-UTRA), IEEE 802.11, IEEE 802.16, IEEE 802.20, and flash-OFDM. UTRA, E-UTRA, and GSM are part of the Universal Mobile Telecommunications System (UMTS). Specifically, Long Term Evolution (LTE) is a UMTS version using E-UTRA. UTRA, E-UTRA, GSM, UMTS, and LTE are described in documents from an organization called the 3rd Generation Partnership Project (3GPP), while cdma2000 is described in documents from an organization called 3rd Generation Partnership Project 2 (3GPP2). These various radio technologies and standards are known or under development. For example, the 3rd Generation Partnership Project (3GPP) is a collaboration between various telecommunications association groups that aims to define globally applicable third-generation (3G) mobile phone specifications. 3GPP Long Term Evolution (LTE) is a 3GPP project aimed at improving the UMTS mobile phone standard. 3GPP defines specifications for next-generation mobile networks, mobile systems, and mobile devices. This disclosure focuses on the evolution of wireless technologies from LTE, 4G, 5G, NR, and beyond, which features shared access to the radio spectrum between networks using new and different sets of radio access technologies or radio air interfaces.

[0042] 5G networks envision a variety of deployments, spectrums, services, and devices that can be implemented using a unified OFDM-based air interface. To achieve these goals, in addition to developing new radio technologies for 5G NR networks, further enhancements to LTE and LTE-A are also considered. 5G NR will be able to scale to provide coverage for: (1) ultra-high density (e.g., approximately 1 M nodes / km) 2 (1) A massive Internet of Things (IoT) with ultra-low complexity (e.g., approximately tens of bits per second), ultra-low energy consumption (e.g., approximately 10+ years of battery life), and deep coverage capable of reaching challenging locations; (2) A large-scale Internet of Things (IoT) with strong security (to protect sensitive personal, financial, or classified information), ultra-high reliability (e.g., approximately 99.9999% reliability), ultra-low latency (e.g., approximately 1 ms), and mission-critical control for users with a wide range of mobility or lack of mobility; and (3) Enhanced mobile broadband, including extremely high capacity (e.g., approximately 10 Tbps / km). 2 Extreme data rates (e.g., multi-Gbps rates, 100+Mbps user experience rates), and deep insights with advanced discovery and optimization.

[0043] 5G NR communication systems can be implemented using optimized OFDM-based waveforms with scalable parameter sets and transmission time intervals (TTIs). Additional features may include a shared, flexible framework for efficiently multiplexing services and features using dynamic low-latency Time Division Duplex (TDD) / Frequency Division Duplex (FDD) designs; and the utilization of advanced wireless technologies such as massive MIMO, robust millimeter-wave (mmWave) transmission, advanced channel decoding, and device-centric mobility. The scalability of parameter design in 5G NR (and the scaling of subcarrier spacing) can efficiently address the operation of diverse services across diverse spectrum and deployments. For example, in various outdoor and macro coverage deployments implemented with FDD / TDD below 3 GHz, subcarrier spacing can occur at 15 kHz, such as over bandwidths (BW) of 5, 10, and 20 MHz. For other various outdoor and small-cell coverage deployments with TDD above 3 GHz, subcarrier spacing can occur at 30 kHz over an 80 / 100 MHz BW. For various other indoor broadband implementations, by using TDD in the unlicensed portion of the 5 GHz band, the subcarrier spacing can occur at 60 kHz over a 160 MHz BW. Finally, for various deployments using mmWave components for TDD at 28 GHz, the subcarrier spacing can occur at 120 kHz over a 500 MHz BW.

[0044] 5G NR's scalable parameter design enables scalable TTIs to meet diverse latency and Quality of Service (QoS) requirements. For example, shorter TTIs can be used for low latency and high reliability, while longer TTIs can be used for higher spectral efficiency. Efficient multiplexing of long and short TTIs allows transmissions to begin at symbol boundaries. 5G NR also envisions a self-contained integrated subframe design that incorporates UL / downlink scheduling information, data, and confirmation within the same subframe. Self-contained integrated subframes support communication in unlicensed or contention-based shared spectrum and support adaptive UL / downlink that can be flexibly configured on a per-cell basis to dynamically switch between UL and downlink to meet current traffic needs.

[0045] Various other aspects and features of this disclosure are further described below. It should be apparent that the teachings herein can be embodied in a variety of forms, and any specific structure, function, or both disclosed herein are merely representative and not limiting. Based on the teachings herein, those skilled in the art will appreciate that the aspects disclosed herein can be implemented independently of any other aspect, and two or more of these aspects can be combined in various ways. For example, any number of aspects set forth herein can be used to implement an apparatus or practice a method. Furthermore, such an apparatus or practice can be implemented using other structures, functionalities, or structures and functionalities that complement or differ from one or more aspects set forth herein. For example, a method can be implemented as part of a system, device, apparatus, and / or as instructions stored on a computer-readable medium for execution on a processor or computer. Moreover, an aspect may include at least one element of the claims.

[0046] Both the UE and BS can each include one or more radio frequency (RF) chains, each of which can include a precoder and amplification devices. The precoder associates the data to be transmitted with output symbols based on the characteristics of the channel on which the data is transmitted. Generally, precoding can be in the form Y = W·x, where x represents the symbols to be transmitted, W is the precoding matrix, and Y is the number of symbols available for transmission based on available resources. In many systems, as discussed below, the precoder can react according to the characteristics of the channel. In many systems, the channel can be analyzed to determine its characteristics.

[0047] In wireless communication, Channel State Information (CSI) refers to the known channel properties of a communication link. CSI indicates how a signal can propagate from the transmitter to the receiver. CSI can represent, for example, the combined effects of scattering, fading, and / or power attenuation with distance between the transmitter and receiver. Channel estimation can be performed to determine these effects on the channel. CSI can be used to adapt transmissions based on current channel conditions, which can contribute to reliable communication, especially in multi-antenna systems with high data rates. CSI is typically estimated, quantized, and fed back to the transmitter at the receiver. CSI can include various feedback information such as Rank Indicator (RI), Channel Quality Indicator (CQI), and / or Precoding Matrix Indicator (PMI). CSI can be used to report radio channel quality information to the BS.

[0048] The UE can receive one or more CSI-RS from the BS, determine channel attributes, determine multiple precoding coefficients based on the channel attributes, and feed the precoding coefficients back to the BS (e.g., in a CSI report). The BS can receive multiple precoding coefficients and apply them to DL beamforming / precoding to provide the UE with optimal DL signal quality.

[0049] This disclosure describes a mechanism for transmitting CSI feedback to reduce CSI payload. In some examples, the BS can utilize codebook-based transmissions to form beams(s) for communication with the UE. The codebook may include a set of FD beamforming components, each identified by an index. FB beamforming components may also be referred to as FB basis vectors, FD basis, or basis vectors. In some aspects, the BS can restrict the UE to a subset of the FD beamforming components in the codebook. For example, the BS can indicate the restricted subset by indicating an index (in various forms) from which the UE can select. By reducing the set of FD beamforming components, complexity and power consumption at the UE can be reduced.

[0050] In some respects, the BS can indicate one or more groups of CSI-RS ports with spatial frequency beamforming. By indicating group information of CSI-RS ports with spatial frequency beamforming, the accuracy of CSI reporting can be improved when DL-UL reciprocity is partial (e.g., in FDD or TDD systems where UL and DL are not transmitted in the same subband), compared to inferring the DL channel state solely through UL probes.

[0051] Figure 1 A wireless communication network 100 according to some aspects of this disclosure is described. Network 100 may be a 5G network. Network 100 includes several base stations (BSs) 105 (labeled 105a, 105b, 105c, 105d, 105e, and 105f, respectively) and other network entities. BS 105 may be a station communicating with UE 115, and may also be referred to as an evolved B-node (eNB), a next-generation eNB (gNB), an access point, etc. Each BS 105 may provide communication coverage for a specific geographic area. In 3GPP, the term "cell" may refer to that specific geographic coverage area of ​​BS 105 and / or the BS subsystem serving that coverage area, depending on the context in which the term is used.

[0052] BS 105 can provide communication coverage for macrocells or small cells (such as picocells or femtocells), and / or other types of cells. Macrocells typically cover a relatively large geographic area (e.g., a radius of several kilometers) and allow unrestricted access by UEs with service subscriptions to a network provider. Small cells (such as picocells) typically cover a relatively small geographic area and allow unrestricted access by UEs with service subscriptions to a network provider. Small cells (such as femtocells) also typically cover a relatively small geographic area (e.g., a residential area) and, in addition to unrestricted access, allow restricted access by UEs associated with that femtocell (e.g., UEs in a closed subscriber group (CSG), UEs of users in that residence, etc.). A BS used for macrocells may be referred to as a macro BS. A BS used for small cells may be referred to as a small cell BS, pico BS, femtocell BS, or home BS. Figure 1 In the examples shown, BS 105d and 105e can be conventional macro BSs, while BS 105a-105c can be macro BSs with one of three-dimensional (3D), full-dimensional (FD), or massive MIMO enabled. BS 105a-105c can leverage its higher-dimensional MIMO capabilities to increase coverage and capacity using 3D beamforming in both elevation and azimuth beamforming. BS 105f can be a small cell BS, which can be a home node or a portable access point. BS 105 can support one or more (e.g., two, three, four, etc.) cells.

[0053] Network 100 can support synchronous or asynchronous operation. For synchronous operation, each BS can have similar frame timing, and transmissions from different BSs can be roughly aligned in time. For asynchronous operation, each BS can have different frame timing, and transmissions from different BSs may not be aligned in time.

[0054] Each UE 115 is distributed throughout the wireless network 100, and each UE 115 may be stationary or mobile. UE 115 may also be referred to as a terminal, mobile station, subscriber unit, station, etc. UE 115 may be a cellular phone, personal digital assistant (PDA), wireless modem, wireless communication device, handheld device, tablet computer, laptop computer, cordless phone, wireless local loop (WLL) station, etc. In one aspect, UE 115 may be a device including a Universal Integrated Circuit Card (UICC). In another aspect, UE may be a device without a UICC. In some aspects, UE 115 without a UICC may also be referred to as an IoT device or an Internet of Things (IoE) device. UE 115a-115d are examples of mobile smartphone-type devices accessing network 100. UE 115 may also be a machine specifically configured for connected communications (including Machine Type Communication (MTC), Enhanced MTC (eMTC), Narrowband IoT (NB-IoT), etc.). UE 115e-115h are examples of various machines configured for communication within access network 100. UE 115i-115k are examples of vehicles equipped with wireless communication devices configured for communication within access network 100. UE 115 can communicate with any type of BS (whether macro BS, small cell, etc.). Figure 1 In this context, the lightning bolt (e.g., a communication link) indicates radio transmissions between UE 115 and serving BS 105, desired transmissions between BSs 105, backhaul transmissions between BSs, or sidelink transmissions between UE 115, where serving BS 105 is the BS designated to serve UE 115 on the downlink (DL) and / or uplink (UL).

[0055] In operation, BS 105a-105c can use 3D beamforming and coordinated spatial technologies (such as Coordinated Multipoint (CoMP) or multi-connectivity) to serve UE 115a and 115b. Macro BS 105d can perform backhaul communication with BS 105a-105c and small cell BS 105f. Macro BS 105d can also deliver multicast services subscribed to and received by UE 115c and 115d. Such multicast services may include mobile TV or streaming video, or may include other services for providing community information (such as weather emergencies or alerts, such as Amber Alerts or Grey Alerts).

[0056] BS 105 can also communicate with the core network. The core network provides user authentication, access authorization, tracking, Internet Protocol (IP) connectivity, and other access, routing, or mobility functions. At least some BS 105s (e.g., examples of gNBs or Access Node Controllers (ANCs)) can interface with the core network via backhaul links (e.g., NG-C, NG-U, etc.) and can perform radio configuration and scheduling for communication with UE 115. In various examples, BS 105s can communicate with each other directly or indirectly (e.g., via the core network) on backhaul links (e.g., X1, X2, etc.), which can be wired or wireless communication links.

[0057] Network 100 can also support mission-critical communication with highly reliable and redundant links for mission-critical devices such as UE 115e, which could be a drone. Redundant communication links with UE 115e may include links from macro BSs 105d and 105e, and links from small cell BS 105f. Other machine-type devices (such as UE 115f (e.g., a thermometer), UE 115g (e.g., a smart meter), and UE 115h (e.g., a wearable device)) can communicate directly with BSs (such as small cell BS 105f and macro BS 105e) via network 100, or be in a multi-step configuration by communicating with another user equipment that relays its information to the network (e.g., UE 115f relays temperature measurement information to smart meter UE 115g, which is then reported to the network via small cell BS 105f). Network 100 can also provide additional network efficiency through dynamic, low latency TDD / FDD communication, such as V2V, V2X, C-V2X communication between UE 115i, 115j or 115k and other UE 115, and / or vehicle-to-infrastructure (V2I) communication between UE 115i, 115j or 115k and BS 105.

[0058] In some implementations, network 100 utilizes OFDM-based waveforms for communication. OFDM-based systems can divide the system BW into multiple (K) orthogonal subcarriers, which are often referred to as subcarriers, frequency modulation, frequency slots, etc. Each subcarrier can be modulated with data. In some instances, the subcarrier spacing between adjacent subcarriers can be fixed, and the total number of subcarriers (K) can depend on the system BW. The system BW can also be divided into subbands. In other instances, the subcarrier spacing and / or the duration of the time interval (TTI) can be scalable.

[0059] In some respects, BS 105 may assign or schedule (e.g., in the form of time-frequency resource blocks (RBs)) transmission resources for downlink (DL) and uplink (UL) transmissions in network 100. DL refers to the transmission direction from BS 105 to UE 115, while UL refers to the transmission direction from UE 115 to BS 105. This communication may take the form of radio frames. Radio frames may be divided into multiple subframes or time slots, for example, about 10. Each time slot may be further divided into sub-time slots. In FDD mode, simultaneous UL and DL transmissions may occur in different frequency bands. For example, each subframe includes UL subframes in the UL band and DL subframes in the DL band. In TDD mode, UL and DL transmissions occur using the same frequency band at different time periods. For example, a subset of subframes in a radio frame (e.g., DL subframes) may be used for DL ​​transmissions, and another subset of subframes in a radio frame (e.g., UL subframes) may be used for UL transmissions.

[0060] DL subframes and UL subframes can be further divided into several regions. For example, each DL or UL subframe may have a predefined region for the transmission of reference signals, control information, and data. Reference signals are predetermined signals that facilitate communication between BS 105 and UE 115. For example, reference signals may have a specific pilot pattern or structure, wherein the pilot frequencies may span the operating BW or frequency band, and each pilot frequency is positioned at a predefined time and predefined frequency. For example, BS 105 may transmit a cell-specific reference signal (CRS) and / or channel state information-reference signal (CSI-RS) to enable UE 115 to estimate the DL channel. Similarly, UE 115 may transmit a probe reference signal (SRS) to enable BS 105 to estimate the UL channel. Control information may include resource allocation and protocol control. Data may include protocol data and / or operational data. In some aspects, BS 105 and UE 115 may communicate using self-contained subframes. Self-contained subframes may include portions for DL ​​communication and portions for UL communication. Self-contained subframes can be DL-centered or UL-centered. DL-centered subframes can include a duration for DL ​​communication that is longer than the duration for UL communication. UL-centered subframes can include a duration for UL communication that is longer than the duration for DL ​​communication.

[0061] In some respects, network 100 may be an NR network deployed on licensed spectrum. BS 105 may transmit synchronization signals (e.g., including primary synchronization signal (PSS) and secondary synchronization signal (SSS)) within network 100 to facilitate synchronization. BS 105 may broadcast system information associated with network 100 (e.g., including primary information block (MIB), residual system information (RMSI), and other system information (OSI)) to facilitate initial network access. In some instances, BS 105 may broadcast PSS, SSS, and / or MIB in the form of synchronization signal block (SSB) on the physical broadcast channel (PBCH) and may broadcast RMSI and / or OSI on the physical downlink shared channel (PDSCH).

[0062] In some respects, UE 115 attempting to access network 100 can perform an initial cell search by detecting a PSS from BS 105. The PSS enables time-period synchronization and indicates a physical layer identity value. UE 115 can subsequently receive an SSS. The SSS enables radio frame synchronization and provides a cell identity value, which can be combined with a physical layer identity value to identify the cell. The PSS and SSS can be located in the center portion of the carrier or at any suitable frequency within the carrier.

[0063] After receiving the PSS and SSS, UE 115 can receive the MIB. The MIB may include system information for initial network access and scheduling information for RMSI and / or OSI. After decoding the MIB, UE 115 can receive the RMSI and / or OSI. The RMSI and / or OSI may include radio resource control (RRC) information related to the Random Access Channel (RACH) protocol, paging, control resource set (CORESET) for monitoring the Physical Downlink Control Channel (PDCCH), Physical UL Control Channel (PUCCH), Physical UL Shared Channel (PUSCH), power control, and SRS.

[0064] After the connection is established, UE 115 and BS 105 can enter the normal operation phase, during which operational data can be exchanged. For example, BS 105 can schedule UE 115 for UL and / or DL ​​communication. BS 105 can transmit UL and / or DL ​​scheduling permission to UE 115 via PDCCH. The scheduling permission can be transmitted in the form of DL control information (DCI). BS 105 can transmit DL communication signals (e.g., carrying data) to UE 115 via PDSCH based on the DL scheduling permission. UE 115 can transmit UL communication signals to BS 105 via PUSCH and / or PUCCH based on the UL scheduling permission.

[0065] In some aspects, network 100 may operate on a system BW or a component carrier (CC) BW. Network 100 may divide the system BW into multiple BWPs (e.g., multiple parts). BS 105 may dynamically assign UE 115 to operate on a particular BWP (e.g., a part of the system BW). The assigned BWP may be referred to as the active BWP. UE 115 may monitor the active BWP to look for signaling information from BS 105. BS 105 may schedule UE 115 to perform UL or DL ​​communication in the active BWP. In some aspects, BS 105 may assign a pair of BWPs within a CC to UE 115 for UL and DL communication. For example, the BWP pair may include one BWP for UL communication and one BWP for DL ​​communication.

[0066] In some aspects, BS 105 and UE 115 can communicate with each other using MIMO and beamforming techniques. For example, BS 105 can transmit a reference signal to UE 115. The reference signal may be referred to as CSI-RS and includes predetermined pilot symbols, allowing UE 115 to estimate the DL channel between BS 105 and UE 115. To facilitate beamforming at BS 105, UE 115 can feed back the CSI (e.g., an estimate of the DL channel) to BS 105. In some aspects, BS 105 can perform precoding to generate a transmission beam with specific directivity and / or specific transmit power. The precoding process may include weighting the signal phase and / or signal amplitude at the antenna elements of BS 105.

[0067] In some aspects, BS 105 and UE 115 may have antenna element arrays and may apply beamforming techniques to communicate with each other. The antenna arrays may be in the form of a single panel or multiple panels. Each antenna panel may include multiple antenna ports or elements in the vertical dimension and multiple antenna ports or elements in the horizontal dimension. In some examples, BS 105 may have a multi-panel antenna and UE 115 may have a single-panel antenna. In some other examples, BS 105 and UE 115 may each have a multi-panel antenna. BS 105 can form a beam in the angular array by weighting the signal phase and amplitude at the antenna elements and can communicate with UE 115 using the optimal beam. The optimal beam can refer to a high-quality beam, for example, where the beam set measured at UE 115 has the highest received signal power.

[0068] Port selection in CSI report

[0069] In some respects, UE 215 can use Type II codebooks for CSI feedback, as in the December 2019 paper titled "3 rdThe description in Section 5.2.2 of 3GPP document TS 38.214 Release 15, “Generation Partnership Project; Technical Specification Group Radio Access Network; NR; Physical layer procedures for data,” is incorporated herein by reference. UE 215 may report CSI based on Type II codebook.

[0070] For port selection in certain systems (e.g., Rel-15 NR port selection), the BS 105 can use a beam as a pre-encoder for CSI-RS. The BS can have N... tx There are several transmit antennas, and the DL channel response matrix for a certain subband can be represented as H. This is achieved by using the corresponding beamforming weights (represented as column vectors w). i Applied to each transmit antenna, the BS 105 can generate antenna ports. A CSI-RS port can refer to the port on which CSI-RS sequences are transmitted. The BS 105 can generate a total of P ports, where P <= N. tx Beamforming weight w i The equivalent DL channel response vector at a specific subband can be equal to Hw i Additionally, for all P ports, the composite equivalent DL channel response matrix can be H. · [w 1, w2,…,w P It has P layers. It should be understood that vectors may also be referred to as components in this disclosure.

[0071] The precoder for the layer on the subband can be given by the following equation (1):

[0072]

[0073] in Represents a vector. This represents the bandwidth amplitude value shared by all sub-bands. This represents the possible different sub-band amplitude values ​​for each sub-band, and φ i This indicates that the subband phase values ​​may be different for each subband. In Equation (1), the top row can represent the beamforming component used for the first polarization, while the bottom row can represent the beamforming component used for the second polarization.

[0074] In this example, UE 115 can select a CSI-RS port instead of a beam. Therefore, using equation (1) in the port selection codebook, if the vector The (i) 11 If the (d+i)th entry is equal to 1 and the rest are 0, then UE 115 can choose the (i)th entry. 11 There are d+i) entry ports. Using this codebook, there are P ports, where the first half is used for polarization 1 and the other half for polarization 2, and the same L ports are used for both polarizations. UE 115 can be accessed via i 11 The report selects L candidate ports, where the first L candidate ports can be 0…L-1, the second L candidate ports can be d…d+L-1, and the last L candidate ports can be…d+L-1. In this scenario, UE 115 can be limited to selecting L coherent ports per subband (e.g., port i). 11 d...i 11 The limit (d+L-1) potentially reduces CSI payload. However, this limitation may lack flexibility and fail to achieve optimal performance. More flexible options could result in larger CSI payload and overhead signaling.

[0075] Port selection for spatial frequency two-dimensional (2D) beamforming in CSI reports

[0076] To overcome the port selection problem discussed above, UE 115 can use a port selection codebook with spatial frequency 2D beamforming (e.g., Rel-17 NR port selection with spatial frequency 2D beamforming) to report port selections. For example, using a Type II port selection codebook with spatial frequency beamforming, UE 115 can transmit a reference signal (e.g., SRS) to BS 105, which receives the reference signal and generates multiple wideband beamforming ports. For example, BS 105 can estimate the UL channel state of each subband and determine multiple DL spatial domain (SD) beamforming weight components for each subband based on DL-UL reciprocity. Subsequently, BS 105 can determine multiple DL frequency domain (FD) beamforming weight components for each SD beamforming weight component based on the corresponding weight values ​​for all subbands. Additionally, BS 105 can determine the broadband beamforming port by linearly combining multiple weighted broadband beamforming weight components (considered as spatial frequency 2D beamforming) used for one or more SD beamforming weight components and one or more FD beamforming weight components.

[0077] BS 105 can transmit to UE 115 a broadband CSI-RS with broadband beamforming ports and an additional CSI report configuration message, wherein the CSI report configuration message indicates that the CSI report is based on port selection with these CSI-RS ports. UE 115 can receive the broadband CSI-RS with broadband beamforming ports and the CSI report configuration message from BS 105, select multiple received broadband CSI-RS ports, and combine them with corresponding coefficients for each port. UE 115 can then report the port selection results and corresponding coefficients from the CSI report to BS 105.

[0078] The expression for spatial frequency 2D beamforming can be represented in various ways. For example, if the broadband beamforming port uses a transmit antenna with one polarization, the precoding matrix can be generated according to equation (2):

[0079]

[0080] Where W is a matrix, L represents the number of SD beamforming weight components, M represents the number of FD beamforming weight components, m represents the index of the candidate FD beamforming component set (e.g., all possible FD beamforming components), and b i f represents the SD beamforming weight component. m This represents the FD beamforming weight component, and d i，m This represents the bandwidth coefficients. Each column of W represents a precoded component (e.g., a precoded vector) of a subband. In other examples, these precoded components may be different.

[0081] In another example, if the broadband beamforming port uses a transmit antenna with two polarizations, then the precoding matrix for each polarization (denoted as W1, W2) has the same form as W. SD beamforming weight components {b i} and FD beamforming weight components (f m These two polarizations can be the same or different.

[0082] In some respects, CSI-RS port precoding and selection can be polarization-shared or polarization-specific. For polarization-shared port selection, the same port can be used for each polarity. In some examples, the BS 105 can use the same precoder on corresponding ports of different polarities. In some examples, the UE 115 assumes an organization for CSI-RS. This organization can be configured by the BS 105 or specified in the radio standard.

[0083] For polarization-shared port selection, the first half of the CSI-RS ports can use the transmit antenna on polarization 1, while the other half can use the transmit antenna on polarization 2, where these two polarizations may have the same SD beamforming weight components; although other non-uniform port splitting of the polarization is possible. It can be precoded (per port) similarly to the second half of the CSI-RS ports.

[0084] With the help of polarization-shared port selection, the PMI of a layer on any of the N3 FD cells can be provided according to equation (3):

[0085]

[0086] in, Size is And walk i k There is only one "1" in row i (if row i) k If there is only one "1" in the N3 FD units, then the i-th FD unit is selected. k (ports), where P is the total number of CSI-RS ports, c k Indicates port i on polarization 1 k The associated linear combination coefficients (these are broadband coefficients), Indicates the port i on polarization 2 k The associated linear combination coefficients (which are bandwidth coefficients), and K0 / 2 represents the number of CSI-RS ports that the UE can use to generate linear combinations to calculate the PMI in equation (3). UE 115 can report CSI-RS ports. and port coefficient or port coefficient A subset of the data, where the unreported port coefficients are set to 0.

[0087] For port selection that varies depending on polarization, the BS 105 can use different precoders on CSI-RS ports with different polarizations. For example, the first portion of the CSI-RS ports (e.g., 20 CSI-RS ports) can use transmit antennas on polarization 1, and the second portion of the CSI-RS ports (e.g., 12 CSI-RS ports) can use transmit antennas on polarization 2. In some examples, the UE 115 can select any CSI-RS port for combination.

[0088] With the help of polarization-dependent port selection, the PMI of a layer on any FD cell of N3 FD cells can be provided according to equation (4):

[0089]

[0090] in, Size is P x 1 and row i k There is only one "1" (selecting the i-th element from all N3 FD units). k (ports), where P is the total number of CSI-RS ports, c k Indicates the connection with port i k The associated linear combination coefficients, and K0 represents the multiple CSI-RS ports used by the UE to generate the linear combination to calculate the PMI in equation (4). UE 115 can report CSI-RS ports. and port coefficient or port coefficient A subset of the data, where the unreported port coefficients are set to 0.

[0091] Therefore, compared to Rel-15 NR port selection, using the port selection codebook with spatial frequency 2D beamforming discussed in Rel-17 can reduce the CSI feedback payload because, for example, the port selection results reported by UE 115 are for broadband usage rather than for each subband. Furthermore, when DL-UL reciprocity is fair (e.g., in FDD or TDD systems where UL and DL are not transmitted in the same subband), using the port selection codebook with spatial frequency 2D beamforming discussed in Rel-17 can improve the accuracy of CSI reporting compared to inferring the DL channel state solely through UL probing.

[0092] Frequency compression in CSI reports

[0093] To overcome the problem of excessive CSI signaling overhead discussed above, UE 115 can use a Type II candidate with frequency compression (e.g., Rel-16 NR) to report port selection(s). For example, by means of a Type II codebook with FD compression or a Type II port selection codebook, UE 115 can be configured to report FD-compressed precoder feedback to reduce the overhead of CSI reporting.

[0094] In some examples, BS 105 transmits CSI-RS to UE 115, UE 115 determines PMI and transmits a CSI report to BS 105 based on the received CSI-RS. By performing codebook operations with FD compression on a layer, UE 115 can utilize the sparsity of the spatial and frequency domains by determining the compressed Type II precoder W according to Equation (5):

[0095]

[0096] Where W represents the compressed Type II precoder, and W1 is a matrix representing the SD beamforming components comprising L beams per polarization group (e.g., L columns) (e.g., thus a total of 2L beams). It is a matrix and includes multiple candidate linear combination coefficients (e.g., all required linear combination coefficients) (including amplitude and phase), where each element represents a coefficient of the beam tap, and It is a matrix composed of components (each row being a component) used to perform compression in FD. f The components in the matrix can be derived from a specific number of columns in the Discrete Fourier Transform (DFT) matrix.

[0097] UE 115 can display W1 of all layers. and The quantization results are reported as PMI. For Type II port selection codebooks with frequency compression, if the BS 105 uses one or more SD beamforming components at the CSI-RS port, the UE115 can simply determine and report... and In this example, it is not necessary to request UE 115 to determine and report the SD beamforming component matrix W1.

[0098] Channel estimation and port selection

[0099] UE 115 may have difficulty estimating the channel or selecting the port. For example, for a Type II codebook with FD compression (with or without port selection), BS 105 does not report W to the UE. f The FD beamforming components in the BS 105 provide any information or limitations. UE 115 can transmit SRS to BS 105, from which BS 105 can derive information about the radio channel. BS 105 may wish to provide some guidance to UE 115 in selecting FD beamforming components. In doing so, this can help UE 115 determine the optimal FD beamforming components. Furthermore, due to the smaller subset of available FD beamforming components, computational complexity can be reduced at UE 115, potentially saving energy at UE 115.

[0100] Additionally, for Type II port selection codebooks with spatial frequency beamforming, for polarization-shared port selection or polarization-dependent port selection, UE 115 can estimate the channel gain for each received CSI-RS port, select multiple CSI-RS ports, and combine them with the corresponding coefficients for each port. UE 115 may not be aware of the FD beamforming components used by BS 105. On one hand, the power delay distribution of an FD-beamformed channel may shift or be displaced compared to a channel without FD beamforming, potentially making it difficult for UE 115 to determine which time-domain window of the power delay distribution should be used. Therefore, in this case, channel estimation performance may be worse than without FD beamforming. On the other hand, without FD beamforming information, UE 115 may have difficulty determining or recovering the non-beamformed channel response matrix, potentially making it difficult for UE 115 to select the optimal port and determine the port combination coefficients that may result in the maximum combined beamforming gain. It may be desirable for BS 105 to indicate information about spatial frequency 2D beamforming in CSI-RS port generation so that UE 115 can improve channel estimation performance and derive better or optimal port selection results and port combination coefficients.

[0101] CSI Reporting Framework

[0102] Figure 2 The wireless communication network 200, which implements one or more aspects of this disclosure, as reported in the CSI report, is described. Network 200 may correspond to a portion of network 100. For the purpose of simplifying the discussion, Figure 2 The BS205 communicating with UE 215 has been described, but it will be appreciated that the various embodiments of this disclosure can be scaled to many more UE 215s and / or BS 205s. UE 215 may be similar to UE 115, and BS 205 may refer to BS 105. BS 205 may include a radio frequency (RF) front end configured for wireless signal transmission and reception.

[0103] As discussed above, BS 205 can utilize codebook-based transmissions to form beams 212(s) for communication with UE 215. For example, BS 205 can perform precoding to generate beams 212a and 212b based on the codebook. The codebook can be in the form of one or more matrices, which may include selection of beams, weights for scaling amplitude and / or phase at antenna elements and / or antenna ports of BS 205. In some instances, the antenna ports may be dummy antenna ports, which may or may not have a direct mapping to physical antenna elements at BS 205. In some instances, the codebook may have a codebook structure (e.g., single or dual) including a wideband matrix and / or a frequency-selective subband matrix. The codebook may be a predetermined or pre-configured codebook known to both BS 205 and UE 215.

[0104] exist Figure 2 In the illustrated example, the optimal beam 212 from BS 205 to UE 215 can correspond to beams 212a and 212b (shown as pattern-filled beams). In some instances, beams 212a and / or 212b can reach UE 215 via a direct line-of-sight (LOS) path. In some instances, beams 212a and / or 212b can reach UE 215 via a non-directional LOS path, for example, from a scatterer or cluster in the environment. UE 215 can select the optimal beams 212a and 212b, and the weights for the amplitude and / or phase of beams 212a and 212b, from a codebook.

[0105] UE 215 can potentially select any candidate FD beamforming component (e.g., index) from the codebook. The selection of an FD beamforming component can also refer to the selection of an index corresponding to that FD beamforming component. For example, if an index references or identifies an FD beamforming component, then the index corresponds to that FD beamforming component. To facilitate UE 215's selection of the optimal beam(s) 212 (e.g., determining the optimal FD beamforming component) and / or reduce computational complexity at UE 215, BS 205 can restrict UE 215 to selecting a subset of candidate FD beamforming components from the codebook. In some aspects, BS 205 can transmit to UE 215 an indication of the restricted set of FD beamforming components 210. BS 205 can transmit the indication of the restricted set of FD beamforming components 210 via, for example, RRC signaling messages, MAC control elements (MAC CE), and / or in the DCI.

[0106] Additionally, BS 205 may transmit a set of CSI-RS 214 to UE 215 using one or more beams 212. Each CSI-RS 214 may include a predetermined sequence or a predetermined pilot symbol sequence. BS 205 may transmit CSI-RS 214 at configured time and frequency locations and using one or more configured beams 212. Additionally, BS 205 may use different beams 212 and / or different combinations of beams 212 at different times and frequencies to transmit CSI-RS 214. BS 205 may configure UE 215 for CSI-RS 214 transmission using configured time and frequency resources and configured beams(s).

[0107] UE 215 can receive an indication of the restricted set of the FD beamforming component 210 and CSI-RS(s) 214. UE 215 can perform measurements on CSI-RS(s) 214, determine channel attributes based on CSI-RS(s) 214, and determine multiple precoding coefficients based on the channel attributes. For example, UE 215 can determine multiple precoding coefficients based on the restricted set of the FD beamforming component 210 and CSI-RS(s) 214. UE 215 can feed back these multiple precoding coefficients to BS 205, which can apply these precoding coefficients to DL beamforming / precoding to provide UE 215 with optimal DL signal quality. For example, UE 215 can transmit a CSI report 220 indicating the multiple precoding coefficients to BS 205.

[0108] FD beamforming components

[0109] FD beamforming components can include various vectors. For example, FD beamforming components can include discrete Fourier transform (DFT) vectors. BS 205 can determine the beamforming weights of the DFT vectors according to the following equation (6):

[0110]

[0111] Where N represents the number of sub-bands included in multiple FD beamforming components or the number of FD beamforming components. This represents the complete set of indexes for multiple FD beamforming components, and m represents the indexes of multiple FD beamforming components (e.g., ...). The plurality of FD beamforming components may include a set of all possible FD beamforming components or indices (e.g., in a codebook), and the restricted set of FD beamforming components 210 may be a subset of the plurality of FD beamforming components. Additionally, the number of subbands may be equal to the number of FD beamforming components.

[0112] In another example, the FD beamforming component may include a discrete cosine transform (DCT) vector. BS 205 can determine the beamforming weights of the DCT vector according to the following equation (7):

[0113]

[0114] Where N represents the number of sub-bands included in multiple FD beamforming components or the number of FD beamforming components. This represents the complete set of indexes for multiple FD beamforming components, and m represents the indexes of multiple FD beamforming components (e.g., ...). The plurality of FD beamforming components may include a set of all possible FD beamforming components or indices (e.g., in a codebook), and the restricted set of FD beamforming components 210 may be a subset of the plurality of FD beamforming components. Additionally, the number of subbands may be equal to the number of FD beamforming components.

[0115] Indication of one or more discrete indices (coherent and / or non-coherent indices) for FD beamforming components.

[0116] BS 205 can transmit an indication of the restricted set of FD beamforming component 210 in several ways. BS 205 can transmit this indication by transmitting an index set of the restricted set of FD beamforming component 210 for multiple CSI-RS ports, where each CSI-RS port corresponds to an FD beamforming component with a corresponding index of that index set. BS 205 can also transmit the restricted set of FD beamforming component 210 by transmitting one or more discrete indices of the FD beamforming component, where the one or more discrete indices correspond to the restricted set of that FD beamforming component.

[0117] In some aspects, the one or more discrete indices may include coherent indices of the FD beamforming components and / or may include non-coherent indices of the FD beamforming components. In one example, BS 205 may transmit an indication of the one or more discrete indices to UE 215 by transmitting an indication of a bitmap. Each bit in the bitmap with a first value corresponds to an index included in the one or more discrete indices, while each bit in the bitmap with a second value corresponds to an index not included in the one or more discrete indices. In this example, BS 205 may indicate a bitmap of length N bits, where each bit indicates whether the corresponding index is included. In, or the value of the selected index can be indicated one by one, where N represents the number of sub-bands included in the plurality of FD beamforming components or the number of FD beamforming components, where Represents the set of restricted FD base indices, and The indexes in the data are not necessarily continuous (e.g., The codebook may include a set of FD bases, each FD base being identified by an index. BS 205 may restrict UE 215 to a subset of the FD bases in the codebook. BS 205 may indicate the restricted subset by indicating the indexes (in various forms) from which UE 115 may select. The plurality of FD beamforming components may include a set of all possible FD beamforming components or indices (e.g., in the codebook), and the restricted set of FD beamforming components 210 may be a subset of the plurality of FD beamforming components.

[0118] Additionally or alternatively, BS 205 may transmit an indication of the one or more discrete indices by transmitting an indication of a first number of FD beamforming components included in a restricted set of FD beamforming components 210 and by transmitting an integer less than or equal to a combined value. The first number may be denoted as N', and the combined value may be denoted as... Given a set (with a total of N indices), find the number of possible results for selecting N' indices, and... A complete set of indexes can represent multiple FD beamforming components. These multiple FD beamforming components may include a set of all possible FD beamforming components or indexes (e.g., in a codebook), and a restricted set of FD beamforming components 210 may be a subset of these multiple FD beamforming components.

[0119] In some respects, BS 205 determines the combination value according to the following formula (8):

[0120]

[0121] Where N represents the magnitude of the plurality of FD beamforming components, N' represents the first number of FD beamforming components, and (0 to N') Each integer in ) represents the number of FD beamforming components. The result is the selection of a first number (N') of FD beamforming components. Multiple FD beamforming components can be (e.g., in a codebook) the set of all possible FD beamforming components.

[0122] Additionally, the number of quantization bits can be provided according to the following formula (9):

[0123]

[0124] Indication for an index window spanning a coherent index

[0125] In some aspects, BS 205 transmits the restricted set of FD beamforming components 210 by transmitting an indication of an index window including a start index and an end index. The index window may span multiple coherent indices of the FD beamforming components, and the index window may correspond to the restricted set of the FD beamforming components 210. In this example, The indices in may be consecutive, where represents the index of a restricted set of FD beamforming components 210, x represents the start index, 0 <= x <= N - 1, z represents the end index, 0 <= z <= N - 1. If x = z, the restricted set of FD beamforming components 210 includes only one index x of the FD beamforming components. If x < z, the restricted set of FD beamforming components 210 includes the indices from x to z. If x > z, the restricted set of FD beamforming components 210 includes the indices from 0 to z and from x to N - 1.

[0126] In some aspects, BS 205 conveys a restricted set of FD beamforming components 210 by transmitting an indication of an index window including a start index and a length value. The index window may span multiple non - consecutive indices of the FD beamforming components, and the index window may correspond to the restricted set of FD beamforming components 210. The indication of the restricted set of FD beamforming components 210 can be determined according to the following formula (10):

[0127] mod(x + i - 1, N), formula (10).

[0128] where 1 <= i <= y, i represents the index in the restricted set of FD beamforming components 210, the expression mod() represents the modulo operation, N represents the size of the multiple FD beamforming components (e.g., the set of all possible FD beamforming components), x represents the start index, 0 <= x <= N - 1, and y represents the length value, 1 <= y <= N. Additionally, the indices in may be consecutive, where represents the index of a restricted set of FD beamforming components 210.

[0129] Indication of the constrained set of FD beamforming components associated with SD beamforming components and multiple transmission layers.

[0130] In some aspects, BS 205 may use one or more CSI - RS ports belonging to T layers to transmit one or more CSI - RSs, where T is an integer greater than 0. BS 205 can convey an indication of the restricted set of FD beamforming components by indicating the restricted set of FD beamforming components for multiple CSI - RS ports each CSI - RS port is generated by or corresponds to an FD beamforming component with a corresponding index in and where This represents the index of the restricted set of FD beamforming components. UE 215 can receive one or more CSI-RS from BS 215 based on the one or more CSI-RS ports belonging to T layers (used by BS 205), and can receive the restricted set of FD beamforming components for the multiple CSI-RS ports. Instructions.

[0131] In some respects, BS 205 can indicate a restricted set of FD beamforming components for SD beamforming components, for example, for each SD beamforming component, for all SD beamforming components in each of the T layers, and / or for all SD beamforming components in all the T layers. UE 215 can receive one or more CSI-RS from BS 215 based on the one or more CSI-RS ports belonging to the T layers (used by BS 205), and can receive indications for the SD beamforming components in one or more of the T layers.

[0132] Figures 3A-3C This is a diagram illustrating various communication schemes for indicating a restricted set of FD beamforming components of one or more layers, according to one or more aspects of this disclosure. Figures 3A-3C Various aspects can be implemented between UEs (e.g., UEs 115, 215, 415, 515, 615 and / or 700) and BSs (e.g., BSs 105, 205, 405, 505, 605 and / or 800) located in a network (e.g., network 100). Various communication schemes can be adopted, such as those related to... Figure 1 , 2 Similar transmission and / or reporting mechanisms as described in 1, 4, 5, 6, 7, 8, 9, 10, 11 and / or 12 may be used and the same parameter representations as described in this disclosure may be reused.

[0133] exist Figures 3A-3C In this configuration, BS 205 can use CSI-RS ports belonging to three layers (T=3) to transmit CSI-RS, which include layers 302, 304, and 306. BS 205 can use two SD beamforming components (SD beamforming component 310 and SD beamforming component 312) in layer 302 to transmit one or more CSI-RS. Additionally, BS 205 can use two SD beamforming components (SD beamforming component 314 and SD beamforming component 316) in layer 304 to transmit one or more CSI-RS. Additionally, BS 205 can use two SD beamforming components (SD beamforming component 318 and SD beamforming component 319) in layer 306 to transmit one or more CSI-RS. It should be understood that any two SD beamforming components may correspond to different restricted subsets of different layers.

[0134] Although three layers are shown, it should be understood that in other examples, BS 205 may transmit CSI-RS in fewer than three layers or more (e.g., one layer, two layers, four layers, etc.). Additionally, although two SD beamforming components are shown to be transmitted in each layer, it should be understood that in other examples, BS 205 may transmit more than two or fewer SD beamforming components per layer. In some examples, the SD beamforming components at different layers (e.g., SD beamforming component 310 and SD beamforming component 312) are the same.

[0135] exist Figure 3A In this configuration, BS 205 uses communication scheme 300 to transmit an indication of the restricted set of the corresponding FD beamforming component for each SD beamforming component. In scheme 300, BS 205 can transmit an indication regarding whether the CSI-RS port belongs to three layers, each with two SD beamforming components. For each of the T layers, BS 205 can transmit an indication of the restricted set by transmitting the corresponding restricted set for each of the multiple SD beamforming components in the corresponding layer. For example, for layer 302, BS 205 can transmit the first restricted set to UE 215. 320 is used to indicate the SD beamforming component 310, and a second restricted set can be transmitted to the UE 215. 322 is used to indicate the SD beamforming component 312. Additionally, for layer 304, BS 205 can transmit a third restricted set to UE 215. 324 is used to indicate the SD beamforming component 314, and can be transmitted to the UE 215 via a fourth restricted set. 326 is used to indicate the SD beamforming component 316. Additionally, for layer 306, BS 205 can transmit a fifth restricted set to UE 215. 328 indicates the SD beamforming component 318, and can be transmitted to the UE 215 via the sixth restricted set. 330 indicates the SD beamforming component 319.

[0136] exist Figure 3B In this configuration, BS 205 uses communication scheme 301 to transmit indications of the corresponding FD beamforming component restricted sets for all SD beamforming components in each of the T layers. In scheme 301, BS 205 can transmit indications regarding the CSI-RS port belonging to three layers. For each of the T layers, BS 205 can transmit an indication of the restricted set by transmitting the corresponding restricted set for that layer. For example, for layer 302, BS 205 can transmit the first restricted set to UE 215. 340 (which corresponds to) Figure 3A In 320 and The union of 322 is used to indicate SD beamforming components 310 and 312. Additionally, for layer 304, BS 205 can transmit a second restricted set to UE 215. 342 (which corresponds to) Figure 3A In 324 and The union of 326 is used to indicate SD beamforming components 314 and 316. Additionally, for layer 306, BS 205 can transmit a third restricted set to UE 215. 346 (which corresponds to) Figure 3A In 328 and The union of 330 is used to indicate the SD beamforming components 318 and 319.

[0137] exist Figure 3C In this configuration, BS 205 uses communication scheme 303 to transmit indications of the corresponding FD beamforming component restricted sets for all SD beamforming components across all T layers. In scheme 303, BS 205 can transmit indications of restricted sets by transmitting the corresponding restricted sets for all T layers. For example, for layers 302, 304, and 306, BS 205 can transmit the restricted sets to UE 215. 350 (which corresponds to) Figure 3B In 340 342 and The union of 346 is used to indicate the SD beamforming components 310, 312, 314, 216, 318, and 319. The corresponding restricted sets for all T layers can be the restricted sets for the FD beamforming component 210.

[0138] CSI Feedback Based on FD Compression

[0139] UE 215 can be configured to report FD compression feedback (e.g., multiple precoding coefficients) to reduce the overhead of CSI reporting 220. Figure 4 This is a signaling diagram illustrating method 400 for a CSI report associated with FD compression feedback according to one or more aspects of this disclosure. Method 400 may be implemented between UE 415 and BS 405 (e.g., located in network 100). UE 415 may correspond to UE 115, 215, 515, 615 and / or 700, and BS 405 may correspond to BS 105, 205, 505, 605 and / or 800). Method 400 may employ as described above. Figure 1 , 2Similar CSI reporting mechanisms as described in 3A-3C, 5, 6, 7, 8, 9, 10, 11, and / or 12 may be used, and the same parameter representations as described in this disclosure may be reused. As explained, method 400 includes a number of enumerated actions, but embodiments of method 400 may include additional actions before, after, and between these enumerated actions. In some embodiments, one or more of these enumerated actions may be omitted or performed in a different order.

[0140] In action 410, BS 405 transmits an indication of the restricted set of FD beamforming components. For example, BS 405 may transmit the indication via RRC signaling messages, MAC CE, and / or in DCI. In action 420, BS 405 may transmit one or more CSI-RS. UE 415 may receive the indication of the restricted set of FD beamforming components and one or more CSI-RS.

[0141] In action 430, UE 415 determines whether to report a CSI report based on a codebook with FD compression. In one example, BS 205 may transmit a CSI report configuration message instructing UE 415 to transmit the CSI report based on CSI FD compression feedback (e.g., based on a Type II codebook with FD compression, with or without port selection). In another example, the radio standard specifies that UE 415 transmits the CSI report based on CSI FD compression feedback (e.g., adjusting UE 215 to report CSI based on a Type II codebook with FD compression (with or without port selection)).

[0142] In some examples, UE 415 performs actions 440 and 450 in response to a determination of whether to report a CSI report based on a codebook with FD compression (with or without port selection). In action 440, for each SD beamforming component, UE 415 selects one or more FD beamforming components. In one example, UE 415 may select one or more FD beamforming components for an SD beamforming component based on a corresponding indication of a restricted set. UE 415 may determine the coefficient matrix. and FD beamforming component matrix W f W f The index of the FD beamforming components used is included in Among them Represents the set of restricted FD base indices, and The indexes in the data are not necessarily continuous (e.g., The codebook may include a set of FD bases, each identified by an index. BS 205 can restrict UE 215 to a subset of the FD bases in the codebook. BS 205 can indicate the restricted subset by indicating the indices (in various forms) from which UE 415 can select. Therefore, UE 415 can report... The multiple precoded coefficients in the CSI-RS port can be selected and reported to have the highest preconfigured number of coefficients.

[0143] In action 450, for each selected FD beamforming component, UE 415 determines the corresponding coefficients of multiple precoding coefficients based on this indication.

[0144] In action 460, UE 415 transmits a CSI report indicating the multiple precoding coefficients based on a restricted set of one or more received CSI-RS and FD beamforming components. In some instances, the CSI report is associated with a Type I ICSI codebook associated with the BS and / or a Type II codebook associated with the BS with frequency compression (with or without port selection).

[0145] Using some techniques provided by method 400, UE 415 can determine the optimal FD beamforming components and their coefficients, which can improve CSI accuracy and thus increase DL throughput with low computational complexity.

[0146] CSI feedback based on port selection with spatial frequency beamforming

[0147] UE 215 can be configured to report feedback (e.g., multiple precoding coefficients) based on a port selection codebook with spatial frequency beamforming. Figure 5 This is a signaling diagram illustrating a method 500 for reporting a CSI report associated with a port selection codebook having spatial frequency beamforming, according to one or more aspects of this disclosure. Method 500 may be implemented between UE 515 and BS 505 (e.g., located in network 100). UE 515 may correspond to UE 115, 215, 415, 615, and / or 700, and BS 505 may correspond to BS 105, 205, 405, 605, and / or 800). Method 500 may employ methods as described above. Figure 1 , 2 Similar CSI reporting mechanisms to those described in 3A-3C, 4, 6, 7, 8, 9, 10, 11, and / or 12. As explained, method 500 includes several enumerated actions, but embodiments of method 500 may include additional actions before, after, and between these enumerated actions. In some embodiments, one or more of these enumerated actions may be omitted or performed in a different order.

[0148] In action 510, BS 505 transmits an indication of the restricted set of FD beamforming components. For example, BS 505 may transmit the indication via RRC signaling messages, MAC CE, and / or in DCI. In action 520, BS 505 may transmit one or more CSI-RS. BS 505 may use one or more spatial frequency beamforming CSI-RS ports to transmit the one or more CSI-RS. UE 515 may receive the indication of the restricted set of FD beamforming components and one or more CSI-RS. UE 515 may receive the one or more CSI-RS based on one or more spatial frequency beamforming CSI-RS ports at BS 505.

[0149] In action 530, UE 515 determines whether to report a CSI report based on a port selection codebook with spatial frequency beamforming. In one example, BS 205 may transmit a CSI report configuration message instructing UE 515 to transmit the CSI report based on a port selection codebook with spatial frequency beamforming (e.g., a Type II port selection codebook with spatial frequency beamforming). In another example, the radio standard specifies that UE 515 transmits the CSI report based on a port selection codebook with spatial frequency beamforming (e.g., adjusting UE 215 to report CSI based on a Type II port selection codebook with spatial frequency beamforming).

[0150] In some examples, UE 515 performs actions 540 and 550 in response to the determination of a CSI report based on a port selection codebook with spatial frequency beamforming. In action 540, for each selected spatial frequency beamformed CSI-RS port, UE 515 can determine the coefficients of multiple precoding coefficients based on this indication. UE 515 can determine the corresponding coefficients for each spatial frequency beamformed port, where the FD beamforming component is within a corresponding FD beamforming component restricted subset. The instructions are given. In one example, UE 515 can determine a non-FD-beamshaped channel response matrix based on one or more received CSI-RS and an indication of a restricted set for FD beamforming components. UE 515 can determine coefficients based on the non-FD-beamshaped channel response matrix and can select one or more space-frequency beamformed CSI-RS ports by selecting one or more space-frequency beamformed CSI-RS ports with the highest coefficient amplitude. In another example, UE 515 can determine a channel estimation result for one or more space-frequency beamformed CSI-RS ports based on one or more received CSI-RS and an indication of a restricted set for FD beamforming components. UE 515 can determine coefficients based on the channel estimation result and can select one or more space-frequency beamformed CSI-RS ports by selecting one or more space-frequency beamformed CSI-RS ports with the highest coefficient amplitude.

[0151] In action 560, UE 515 transmits a CSI report indicating one or more spatial frequency beamshaped CSI-RS ports and corresponding coefficients (e.g., multiple precoded coefficients) based on a restricted set of one or more received CSI-RS and FD beamforming components. In some instances, the CSI report is associated with a Type II CSI codebook associated with the BS and / or a Type II port selection codebook with spatial frequency beamforming.

[0152] Using some of the techniques provided by Method 500, UE 515 can improve channel estimation performance and derive optimal port selection results and port combination coefficients, which can improve CSI accuracy and thus increase DL throughput.

[0153] Indication of one or more CSI-RS port groups with spatial frequency beamforming

[0154] In some respects, the BS 505 can transmit indications of one or more CSI-RS port groups with spatial frequency beamforming. For example, the BS 505 can transmit indications of CSI-RS port groups corresponding to shared SD beamforming components and different FD beamforming components, or CSI-RS port groups corresponding to shared FD beamforming components and different FD beamforming components. Additionally, by indicating group information of CSI-RS ports with spatial frequency beamforming, the accuracy of CSI reporting can be improved when DL-UL reciprocity is partial (e.g., in FDD or TDD systems where UL and DL are not transmitted in the same subband), compared to inferring the DL channel state solely through UL probes.

[0155] Figure 6This is a signaling diagram illustrating method 600 for a CSI report associated with a CSI-RS port having spatial frequency beamforming, according to one or more aspects of this disclosure. Method 600 may be implemented between UE 615 and BS 605 (e.g., located in network 100). UE 615 may correspond to UE 115, 215, 415, 515, and / or 700, and BS 605 may correspond to BS 105, 205, 405, 505, and / or 800). Method 600 may employ methods as described above. Figure 1 , 2 Similar CSI reporting mechanisms to those described in 3A-3C, 4, 5, 7, 8, 9, 10, 11, and / or 12. As explained, method 600 includes several enumerated actions, but embodiments of method 600 may include additional actions before, after, and between these enumerated actions. In some embodiments, one or more of these enumerated actions may be omitted or performed in a different order.

[0156] In action 610, BS 605 may transmit an indication of one or more CSI-RS port groups with spatial frequency beamforming. In one example, all such CSI-RS ports in each group correspond to a common SD beamforming component and distinct FD beamforming components. In another example, all such CSI-RS ports in each group correspond to a common FD beamforming component and distinct SD beamforming components. UE 615 may receive an indication of one or more CSI-RS port groups with spatial frequency beamforming from BS 605. In some examples, UE 615 may receive a CSI report configuration message that includes an indication of one or more CSI-RS port groups with spatial frequency beamforming.

[0157] In action 620, BS 605 may use one or more spatial frequency beamformed CSI-RS ports to transmit one or more CSI-RS. UE 615 may receive these one or more CSI-RS from BS 605. For example, UE 615 may receive indications for one or more CSI-RS port groups via RRC signaling messages, MAC CE, and / or in DCI.

[0158] In action 630, UE 615 can determine multiple precoding coefficients based on one or more received CSI-RS and the group of one or more CSI-RS ports.

[0159] In action 640, UE 615 can transmit a CSI report indicating the multiple precoding coefficients.

[0160] Figure 7This is a block diagram of an exemplary UE 700 according to one or more aspects of this disclosure. UE 700 may be as described above respectively in Figure 1 , 2 UE 115, UE 215, UE 415, UE 515, and / or UE 615 discussed in sections 4, 5, and / or 6. As shown, UE 700 may include: a processor 702, a memory 704, an FD beamforming module 707, a feedback module 708, a CSI-RS port module 709, a transceiver 710 including a modem subsystem 712 and a radio frequency (RF) unit 714, and one or more antennas 716. These components may communicate directly or indirectly with each other, for example, via one or more buses.

[0161] Processor 702 may include a central processing unit (CPU), digital signal processor (DSP), application-specific integrated circuit (ASIC), controller, field-programmable gate array (FPGA) device, another hardware device, firmware device, or any combination thereof configured to perform the operations described herein. Processor 702 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0162] Memory 704 may include cache memory (e.g., cache memory of processor 702), random access memory (RAM), magnetoresistive RAM (MRAM), read-only memory (ROM), programmable read-only memory (PROM), erasable programmable read-only memory (EPROM), electrically erasable programmable read-only memory (EEPROM), flash memory, solid-state memory device, hard disk drive, other forms of volatile and non-volatile memory, or combinations of different types of memory. In one aspect, memory 704 includes a non-transient computer-readable medium. Memory 704 may store or have instructions 706 recorded thereon. Instructions 706 may include, when executed by processor 702, causing processor 702 to perform the functions described herein in conjunction with aspects of the present disclosure (e.g., references to UE 115, 115, 215, 415, 515, and / or 615). Figure 1 , 2Instructions 706 are the operations described in aspects of 3A-3C, 4, 5, 6, 9, and / or 10. Instruction 706 may also be referred to as program code. Program code can be used to cause a wireless communication device to perform these operations, for example, by causing one or more processors (such as processor 702) to control or command the wireless communication device to do so. The terms "instruction" and "code" should be interpreted broadly to include any type of computer-readable statement. For example, the terms "instruction" and "code" can refer to one or more programs, routines, subroutines, functions, procedures, etc. "Instruction" and "code" can include a single computer-readable statement or many computer-readable statements.

[0163] exist Figure 7 In the example described herein, UE 700 includes an FD beamforming module 707, a feedback module 708, and a CSI-RS port module 709. This is not intended to be limiting, and it should be understood that in other examples, UE 700 may have additional and / or different components. In another example, UE 700 may include a CSI-RS port module 709 and a feedback module 708, but not an FD beamforming module 707.

[0164] The FD beamforming module 707, feedback module 708, and / or CSI-RS port module 709 can be implemented via hardware, software, or a combination thereof. For example, the FD beamforming module 707, feedback module 708, and / or CSI-RS port module 709 can be implemented as a processor, circuitry, and / or instructions 706 stored in memory 704 and executed by processor 702. In some instances, the FD beamforming module 707, feedback module 708, and / or CSI-RS port module 709 can be integrated within the modem subsystem 712. For example, the FD beamforming module 707, feedback module 708, and / or CSI-RS port module 709 can be implemented by a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 712.

[0165] The FD beamforming module 707, feedback module 708, and / or CSI-RS port module 709 can be used in various aspects of this disclosure, for example, Figure 1 , 2 The FD beamforming module 707 may be configured, for example, to receive from the BS an indication of a restricted set of FD beamforming components. The CSI-RS port module 709 may be configured to receive one or more CSI-RS signals from the BS. The feedback module 708 may be configured to transmit a CSI report indicating multiple precoding coefficients based on the received one or more CSI-RS signals and the restricted set of FD beamforming components.

[0166] In some aspects, the CSI-RS port module 709 can be configured to receive from the BS an indication of one or more CSI-RS port groups having spatial frequency beamforming. The CSI-RS port module 709 can be configured to receive one or more CSI-RS from the BS. The feedback module 708 can be configured to transmit a CSI report indicating multiple precoding coefficients based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0167] As shown, transceiver 710 may include modem subsystem 712 and RF unit 714. Transceiver 710 may be configured to communicate bidirectionally with other devices, such as BS 105, 205, 405, 505, 605, 800 and / or another core network element. Modem subsystem 712 may be configured to modulate and / or encode data from memory 704, FD beamforming module 707, feedback module 708 and / or CSI-RS port module 709 according to a modulation and coding scheme (MCS), such as low-density parity-check (LDPC) coding scheme, turbo coding scheme, convolutional coding scheme, polarization coding scheme, digital beamforming scheme, etc. RF unit 714 can be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated / coded data transmitted from modem subsystem 712 (over out-of-band transmission) or from another source (such as UE 115 or BS 105). This data includes modulated / coded data such as CSI-RS reports, CSI feedback, CSI-RS, multiple precoding coefficients, indications of restricted sets of FD beamforming components, and indications of one or more CSI-RS port groups with spatial frequency beamforming. RF unit 714 can be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as integrated together in transceiver 710, modem subsystem 712 and RF unit 714 can be separate devices coupled together at UE 115 to enable UE 115 to communicate with other devices.

[0168] RF unit 714 can provide modulated and / or processed data (e.g., data packets (or more generally, data messages containing one or more data packets and other information)) to antenna 716 for transmission to one or more other devices. Antenna 716 can further receive data messages transmitted from other devices. Antenna 716 can provide received data messages for processing and / or demodulation at transceiver 710. Transceiver 710 can provide demodulated and decoded data (e.g., CSI-RS reports, CSI feedback, CSI-RS, multiple precoding coefficients, indications of restricted sets of FD beamforming components, and indications of one or more CSI-RS port groups with spatial frequency beamforming, etc.) to FD beamforming module 707, feedback module 708, and / or CSI-RS port module 709 for processing. Antenna 716 may include multiple antennas of similar or different designs to maintain multiple transmission links. RF unit 714 can configure antenna 716.

[0169] In one aspect, transceiver 710 can coordinate with FD beamforming module 707 to receive indications of a restricted set of FD beamforming components from the BS. Transceiver 710 can coordinate with CSI-RS port module 709 to receive one or more CSI-RS from the BS. Transceiver 710 can also coordinate with feedback module 708 to transmit a CSI report indicating multiple precoding coefficients to the BS based on the received one or more CSI-RS and the restricted set of FD beamforming components.

[0170] On one hand, transceiver 710 can coordinate with CSI-RS port 709 to receive from the BS indications of one or more CSI-RS port groups having spatial frequency beamforming. Transceiver 710 can coordinate with CSI-RS port module 709 to receive one or more CSI-RS from the BS. Transceiver 710 can also coordinate with feedback module 708 to transmit a CSI report indicating multiple precoding coefficients to the BS based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0171] In one aspect, UE 700 may include multiple transceivers 710 implementing different RATs (e.g., NR and LTE). In another aspect, UE 700 may include a single transceiver 710 implementing multiple RATs (e.g., NR and LTE). In yet another aspect, transceiver 710 may include various components, wherein different combinations of the components can implement different RATs.

[0172] Figure 8 This is a block diagram of an exemplary BS 800 according to one or more aspects of this disclosure. The BS 800 may be as described above respectively in... Figure 1 , 2The BS 105, BS 205, BS 405, BS 505, and / or BS 605 discussed in sections 4, 5, and / or 6. As shown, the BS 800 may include: a processor 802, a memory 804, an FD beamforming module 807, a feedback module 808, a CSI-RS port module 809, a transceiver 810 including a modem subsystem 812 and an RF unit 814, and one or more antennas 816. These components may communicate directly or indirectly with each other, for example, via one or more buses.

[0173] Processor 802 may have various features as a special-purpose processor. For example, these features may include a CPU, DSP, ASIC, controller, FPGA device, another hardware device, firmware device, or any combination thereof configured to perform the operations described herein. Processor 802 may also be implemented as a combination of computing devices, such as a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors combined with a DSP core, or any other such configuration.

[0174] Memory 804 may include cache memory (e.g., the cache memory of processor 802), RAM, MRAM, ROM, PROM, EPROM, EEPROM, flash memory, solid-state memory devices, one or more hard disk drives, memristor-based arrays, other forms of volatile and non-volatile memory, or combinations of different types of memory. In some aspects, memory 804 may include a non-transient computer-readable medium. Memory 804 may store instructions 806. Instructions 806 may include causing processor 802 to perform the operations described herein when executed by processor 802 (e.g., ...). Figure 1 , 2 Instructions 806 (including aspects of 3A-3C, 4, 5, 6, 11, and / or 12). Instructions 806 can also be referred to as codes, which can be broadly interpreted as including those referenced above. Figure 7 Any type of computer-readable statement discussed.

[0175] exist Figure 8 In the example described herein, BS 800 includes an FD beamforming module 807, a feedback module 808, and a CSI-RS port module 809. This is not intended to be limiting, and it should be understood that in other examples, BS 800 may have additional and / or different components. In another example, BS 800 may include the CSI-RS port module 809 and the feedback module 808, but not the FD beamforming module 807.

[0176] The FD beamforming module 807, feedback module 808, and / or CSI-RS port module 809 can be implemented via hardware, software, or a combination thereof. For example, the FD beamforming module 807, feedback module 808, and / or CSI-RS port module 809 can be implemented as a processor, circuitry, and / or instructions 806 stored in memory 804 and executed by processor 802. In some instances, the FD beamforming module 807, feedback module 808, and / or CSI-RS port module 809 can be integrated within the modem subsystem 812. For example, the FD beamforming module 807, feedback module 808, and / or CSI-RS port module 809 can be implemented by a combination of software components (e.g., executed by a DSP or general-purpose processor) and hardware components (e.g., logic gates and circuitry) within the modem subsystem 812.

[0177] The FD beamforming module 807, feedback module 808, and / or CSI-RS port module 809 can be used in various aspects of this disclosure, for example, Figure 1 , 2 The FD beamforming module 807 can be configured, for example, to transmit to the UE an indication of a restricted set of FD beamforming components. The CSI-RS port module 809 can be configured to transmit one or more CSI-RS signals to the UE. The feedback module 808 can be configured to receive a CSI report indicating multiple precoding coefficients based on the transmitted one or more CSI-RS signals and the restricted set of FD beamforming components.

[0178] In some aspects, the CSI-RS port module 809 can be configured to transmit to the UE an indication of one or more CSI-RS port groups having spatial frequency beamforming. The CSI-RS port module 809 can be configured to transmit one or more CSI-RS to the UE. The feedback module 808 can be configured to receive a CSI report indicating multiple precoding coefficients based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0179] As shown, transceiver 810 may include modem subsystem 812 and RF unit 814. Transceiver 810 may be configured to communicate bidirectionally with other devices, such as UE 115, 215, 415, 515, 605, 700 and / or another core network element. Modem subsystem 812 may be configured to modulate and / or encode data according to MCS (e.g., LDPC coding scheme, turbo coding scheme, convolutional coding scheme, polarization coding scheme, digital beamforming scheme, etc.). RF unit 814 may be configured to process (e.g., perform analog-to-digital conversion or digital-to-analog conversion, etc.) modulated / encoded data transmitted from modem subsystem 812 (in out-of-band transmission) or from another source (such as UE 115 or BS 105) (e.g., CSI-RS reports, CSI feedback, CSI-RS, multiple precoding coefficients, indication of a restricted set of FD beamforming components, and indication of one or more CSI-RS port groups with spatial frequency beamforming, etc.). RF unit 814 can be further configured to perform analog beamforming in conjunction with digital beamforming. Although shown as being integrated together in transceiver 810, modem subsystem 812 and / or RF unit 814 can be separate devices coupled together at BS 105 so that BS 105 can communicate with other devices.

[0180] RF unit 814 may provide modulated and / or processed data (e.g., data packets (or more generally, data messages containing one or more data packets and other information)) to antenna 816 for transmission to one or more other devices. This may include, for example, information transmission for completing attachment to a network and communication with the resident UE 115 or 700 according to some aspects of this disclosure. Antenna 816 may further receive data messages transmitted from other devices and provide the received data messages for processing and / or demodulation at transceiver 810. Transceiver 810 may provide demodulated and decoded data (e.g., CSI-RS reports, CSI feedback, CSI-RS, multiple precoding coefficients, indications of restricted sets of FD beamforming components, and indications of one or more CSI-RS port groups with spatial frequency beamforming, etc.) to FD beamforming module 707, feedback module 708, and / or CSI-RS port module 709 for processing. Antenna 816 may include multiple antennas of similar or different designs to maintain multiple transmission links.

[0181] In one aspect, transceiver 810 can coordinate with FD beamforming module 807 to transmit to the UE an indication of a restricted set of FD beamforming components. Transceiver 810 can coordinate with CSI-RS port module 809 to transmit one or more CSI-RS signals to the UE. Transceiver 810 can also coordinate with feedback module 808 to receive from the BS a CSI report indicating multiple precoding coefficients based on the received one or more CSI-RS signals and the restricted set of FD beamforming components.

[0182] On one hand, transceiver 810 can coordinate with CSI-RS port 809 to transmit to the UE an indication of one or more CSI-RS port groups having spatial frequency beamforming. Transceiver 810 can coordinate with CSI-RS port module 809 to transmit one or more CSI-RS to the UE. Transceiver 810 can also coordinate with feedback module 808 to receive CSI reports from the BS indicating multiple precoding coefficients based on the received one or more CSI-RS and the one or more CSI-RS port groups.

[0183] In one aspect, the BS 800 may include multiple transceivers 810 implementing different RATs (e.g., NR and LTE). In another aspect, the BS 800 may include a single transceiver 810 implementing multiple RATs (e.g., NR and LTE). In yet another aspect, the transceiver 810 may include various components, wherein different combinations of the components can implement different RATs.

[0184] Figure 9 This is a flowchart of a wireless communication method 900 according to one or more aspects of this disclosure. Aspects of method 900 may be performed by a computing device of a wireless communication apparatus (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable means for performing the blocks. For example, a wireless communication apparatus (such as UE 115, 215, 415, 515, 615, and / or 700) may utilize one or more components (such as processor 702, memory 704, FD beamforming module 707, feedback module 708, CSI-RS port module 709, transceiver 710, modem 712, and one or more antennas 716) to perform the steps of method 900. Method 900 may employ methods related to… Figure 1 , 2 Mechanisms similar to those discussed in 3A-3C, 4, 5, 6, and / or 7. As explained, method 900 includes several enumerated boxes, but aspects of method 900 may include additional boxes before, after, and between these enumerated boxes. In some aspects, one or more of the enumerated boxes may be omitted or performed in a different order.

[0185] In block 910, the UE (e.g., UE 115, 215, 415, 515, 615 and / or 700) receives an indication of a restricted set of FD beamforming components. In some instances, the UE may receive an indication of a restricted set of FD beamforming components from the BS using one or more components such as processor 702, FD beamforming module 707, transceiver 710, modem 712 and one or more antennas 716.

[0186] In box 920, the UE (e.g., UE 115, 215, 415, 515, 615 and / or 700) receives one or more Channel State Information Reference Signals (CSI-RS). In some instances, the UE may receive one or more CSI-RS from the BS using one or more components such as processor 702, CSI-RS port module 707, transceiver 710, modem 712 and one or more antennas 716.

[0187] In block 930, the UE (e.g., UE 115, 215, 415, 515, 615, and / or 700) transmits a CSI report indicating multiple precoding coefficients based on a restricted set of one or more received CSI-RS and FD beamforming components. In some instances, the UE may utilize one or more components (such as processor 702, feedback module 708, transceiver 710, modem 712, and one or more antennas 716) to transmit the CSI report to the BS.

[0188] In some instances, the feedback module 708 is associated with a Type II CSI codebook associated with BS 605 and / or a Type II codebook associated with BS that has frequency compression (with or without port selection).

[0189] Figure 10 This is a flowchart of a wireless communication method 1000 according to one or more aspects of this disclosure. Aspects of method 1000 may be performed by a computing device of a wireless communication apparatus (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable means for performing the blocks. For example, a wireless communication apparatus (such as UE 115, 215, 415, 515, 615, and / or 700) may utilize one or more components (such as processor 702, memory 704, FD beamforming module 707, feedback module 708, CSI-RS port module 709, transceiver 710, modem 712, and one or more antennas 716) to perform the steps of method 1000. Method 1000 may employ methods related to… Figure 1 , 2Mechanisms similar to those discussed in 3A-3C, 4, 5, 6, and / or 7. As explained, method 1000 includes several enumerated boxes, but aspects of method 1000 may include additional boxes before, after, and between these enumerated boxes. In some aspects, one or more of the enumerated boxes may be omitted or performed in a different order.

[0190] In block 1010, the UE (e.g., UE 115, 215, 415, 515, 615 and / or 700) receives indications for one or more Channel State Information Reference Signal (CSI-RS) port groups with spatial frequency beamforming. In some instances, the UE may receive indications from the BS using one or more components such as processor 702, CSI-RS port module 709, transceiver 710, modem 712 and one or more antennas 716.

[0191] In box 1020, the UE (e.g., UE 115, 215, 415, 515, 615 and / or 700) receives one or more CSI-RS. In some instances, the UE may receive one or more CSI-RS from the BS using one or more components such as processor 702, CSI-RS port module 709, transceiver 710, modem 712 and one or more antennas 716.

[0192] In box 1030, the UE (e.g., UE 115, 215, 415, 515, 615, and / or 700) transmits a CSI report indicating multiple precoding coefficients based on one or more received CSI-RS and the group of one or more CSI-RS ports. In some instances, the UE may utilize one or more components (such as processor 702, feedback module 708, transceiver 710, modem 712, and one or more antennas 716) to transmit the CSI report to the BS.

[0193] In some instances, the feedback module 708 is associated with a Type II CSI codebook associated with the BS and / or a Type II port selection codebook with spatial frequency beamforming associated with the BS.

[0194] Figure 11This is a flowchart of a wireless communication method 1100 according to one or more aspects of this disclosure. Aspects of method 1100 may be performed by a computing device of a wireless communication apparatus (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable means for performing the blocks. For example, a wireless communication apparatus (such as BS 105, 205, 405, 505, 605, and / or 800) may utilize one or more components (such as processor 802, memory 804, FD beamforming module 807, feedback module 808, CSI-RS port module 809, transceiver 810, modem 812, and one or more antennas 816) to perform the steps of method 1100. Method 1100 may employ methods related to… Figure 1 , 2 Mechanisms similar to those discussed in 3A-3C, 4, 5, 6, and / or 8. As explained, method 1100 includes several enumerated boxes, but aspects of method 1100 may include additional boxes before, after, and between these enumerated boxes. In some aspects, one or more of the enumerated boxes may be omitted or performed in a different order.

[0195] In block 1110, the BS (e.g., BS 105, 205, 405, 505, 605 and / or 800) transmits an indication of a restricted set of frequency domain (FD) beamforming components. In some instances, the BS may use one or more components (such as processor 802, FD beamforming module 807, transceiver 810, modem 812, and one or more antennas 816) to transmit the indication of a restricted set of FD beamforming components to the UE.

[0196] In box 1120, the BS (e.g., BS 105, 205, 405, 505, 605 and / or 800) transmits one or more CSI-RS. In some instances, the BS may transmit the one or more CSI-RS to the UE using one or more components such as processor 802, CSI-RS port module 809, transceiver 810, modem 812 and one or more antennas 816.

[0197] In block 1130, the BS (e.g., BS 105, 205, 405, 505, 605, and / or 800) receives a CSI report indicating multiple precoding coefficients based on a restricted set of one or more transmitted CSI-RS and FD beamforming components. In some instances, the BS may utilize one or more components (such as processor 802, feedback module 808, transceiver 810, modem 812, and one or more antennas 816) to receive the CSI report from the UE.

[0198] In some instances, the feedback module 808 is associated with a Type II CSI codebook associated with the BS and / or a Type II codebook associated with the BS with frequency compression (with or without port selection).

[0199] Figure 12 This is a flowchart of a wireless communication method 1200 according to one or more aspects of this disclosure. Aspects of method 1200 may be performed by a computing device of a wireless communication apparatus (e.g., a processor, processing circuitry, and / or other suitable components) or other suitable means for performing the blocks. For example, a wireless communication apparatus (such as BS 105, 205, 405, 505, 605, and / or 800) may utilize one or more components (such as processor 802, memory 804, FD beamforming module 807, feedback module 808, CSI-RS port module 809, transceiver 810, modem 812, and one or more antennas 816) to perform the steps of method 1200. Method 1200 may employ methods related to… Figure 1 , 2 Mechanisms similar to those discussed in 3A-3C, 4, 5, 6, and / or 8. As explained, method 1200 includes several enumerated boxes, but aspects of method 1200 may include additional boxes before, after, and between these enumerated boxes. In some aspects, one or more of the enumerated boxes may be omitted or performed in a different order.

[0200] In block 1210, the BS (e.g., BS 105, 205, 405, 505, 605 and / or 800) transmits indications to one or more CSI-RS port groups with spatial frequency beamforming. In some instances, the BS may use one or more components (such as processor 802, CSI-RS port module 809, transceiver 810, modem 812, and one or more antennas 816) to transmit indications to the UE to one or more CSI-RS port groups with spatial frequency beamforming.

[0201] In box 1220, the BS (e.g., BS 105, 205, 405, 505, 605, and / or 800) uses one or more CSI-RS port groups to transmit one or more CSI-RS. In some instances, the BS may use one or more components (such as processor 802, CSI-RS port module 809, transceiver 810, modem 812, and one or more antennas 816) to transmit the one or more CSI-RS to the UE using the one or more CSI-RS port groups.

[0202] In box 1230, the BS (e.g., BS 105, 205, 405, 505, 605, and / or 800) receives a CSI report indicating multiple precoding coefficients based on one or more transmitted CSI-RS and the group of ports of the one or more CSI-RS. In some instances, the BS may utilize one or more components (such as processor 802, feedback module 808, transceiver 810, modem 812, and one or more antennas 816) to receive the CSI report from the UE.

[0203] In some instances, the feedback module 808 is associated with a Type II CSI codebook associated with the BS and / or a Type II port selection codebook with spatial frequency beamforming associated with the BS.

[0204] Information and signals can be represented using any of a wide variety of different techniques and technologies. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be mentioned throughout the above description can be represented by voltage, current, electromagnetic waves, magnetic fields or magnetic particles, light fields or light particles, or any combination thereof.

[0205] The various illustrative blocks and modules described herein can be implemented or executed using a general-purpose processor, DSP, ASIC, FPGA, or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. The general-purpose processor may be a microprocessor, but in alternatives, the processor may be any conventional processor, controller, microcontroller, or state machine. The processor may also be implemented as a combination of computing devices (e.g., a combination of a DSP and a microprocessor, multiple microprocessors, one or more microprocessors working in conjunction with a DSP core, or any other such configuration).

[0206] The functions described herein can be implemented in hardware, software executed by a processor, firmware, or any combination thereof. If implemented in software executed by a processor, the functions can be stored or transmitted as one or more instructions or code on a computer-readable medium. Other examples and implementations fall within the scope of this disclosure and the appended claims. For example, due to the nature of software, the above-described functions can be implemented using software executed by a processor, hardware, firmware, hardwired, or any combination thereof. Features implementing the functions can also be physically located in various locations, including being distributed such that different parts of the function are implemented at different physical locations. Additionally, as used herein (including in the claims), the use of "or" in an enumeration of items (e.g., an enumeration of items accompanied by phrases such as "at least one of" or "one or more of") indicates an inclusive enumeration, such that an enumeration such as [at least one of A, B, or C] means A or B or C or AB or AC or BC or ABC (i.e., A and B and C).

[0207] As will be appreciated by those skilled in the art by this time, and depending on the specific application at hand, many modifications, substitutions, and variations can be made to the materials, apparatus, configuration, and methods of use of the devices disclosed herein without departing from the spirit and scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the specific embodiments explained and described herein (as they are merely examples), but should be fully equivalent to the appended claims and their functional equivalents.

Claims

1. A wireless communication method, comprising: The user equipment (UE) receives an indication of the restricted set of frequency domain FD beamforming components from the base station (BS). The UE receives one or more Channel State Information Reference Signals (CSI-RS) from the BS; as well as The UE transmits a Channel State Information (CSI) report indicating multiple precoding coefficients to the BS based on one or more received CSI-RS and a limited set of the FD beamforming components.

2. The method of claim 1, comprising: The UE selects one or more FD beamforming components for each spatial domain SD beamforming component based on the indication; as well as For each selected FD beamforming component, the coefficients of the plurality of precoded coefficients are determined.

3. The method of claim 2, comprising: The UE receives from the BS a CSI report configuration message indicating that the CSI report is based on a Type II codebook with frequency compression.

4. The method of claim 2, wherein selecting one or more FD beamforming components comprises selecting one or more FD beamforming components for SD beamforming components based on a corresponding indication to the restricted set.

5. The method of claim 1, comprising: The UE selects one or more spatial frequency beamforming CSI-RS ports based on the indication, wherein receiving one or more CSI-RS includes receiving the one or more CSI-RS based on one or more spatial frequency beamforming CSI-RS ports at the BS; as well as For each selected spatial frequency beamforming CSI-RS port, the coefficients of the plurality of precoding coefficients are determined.

6. The method of claim 5, comprising: The UE receives from the BS a CSI report configuration message indicating that the CSI report is based on a port selection codebook with spatial frequency beamforming.

7. The method of claim 5, comprising: The UE determines a non-FD beamforming channel response matrix based on the received one or more CSI-RS and the indication, wherein determining the coefficients includes determining the coefficients based on the non-FD beamforming channel response matrix, and wherein selecting one or more spatial frequency beamforming CSI-RS ports includes selecting the one or more spatial frequency beamforming CSI-RS ports based on the magnitude of the coefficients.

8. The method of claim 5, comprising: The UE determines a channel estimation result for the one or more spatial frequency beamforming CSI-RS ports based on the received one or more CSI-RS and the indication, wherein determining the coefficients includes determining the coefficients based on the channel estimation result, and wherein selecting the one or more spatial frequency beamforming CSI-RS ports includes selecting the one or more spatial frequency beamforming CSI-RS ports based on the magnitude of the coefficients.

9. The method of claim 1, wherein receiving an indication to a restricted set comprises receiving the indication via a Radio Resource Control (RRC) signaling message.

10. The method of claim 1, wherein receiving an indication to a restricted set comprises receiving the indication via a MAC control element MAC CE.

11. The method of claim 1, wherein receiving an indication to a restricted set comprises receiving the indication in downlink control information (DCI).

12. The method of claim 1, comprising: The UE receives a Channel State Information (CSI) report configuration message, including the indication, from the BS.

13. The method of claim 1, wherein receiving an indication of a restricted set comprises receiving an indication of one or more discrete indices of an FD beamforming component, wherein the one or more discrete indices correspond to a restricted set of the FD beamforming component.

14. The method of claim 13, wherein the one or more discrete indices include coherent indices of the FD beamforming components.

15. The method of claim 13, wherein the one or more discrete indices include the non-coherent indices of the FD beamforming components.

16. The method of claim 13, wherein receiving an indication for one or more discrete indices comprises receiving a bitmap, wherein each bit in the bitmap having a first value corresponds to an index included in the one or more discrete indices, and each bit in the bitmap having a second value corresponds to an index not included in the one or more discrete indices.

17. The method of claim 16, wherein the bitmap has a length of N bits, where N represents the number of subbands included in the plurality of FD beamforming components or the number of FD beamforming components, and the restricted set is a subset of the plurality of FD beamforming components.

18. The method of claim 1, wherein receiving an indication of a restricted set comprises receiving an indication of an index window comprising a start index and an end index, the index window spanning a plurality of coherent indices of the FD beamforming component, and the index window corresponding to a restricted set of the FD beamforming component.

19. The method of claim 1, wherein receiving an indication of a restricted set comprises receiving an indication of an index window comprising a start index and a length value, the index window spanning a plurality of discontinuous indices of the FD beamforming component, and the index window corresponding to a restricted set of the FD beamforming component.

20. The method of claim 1, wherein the FD beamforming component in the constrained set comprises a Discrete Fourier Transform (DFT) vector or a Discrete Cosine Transform (DCT) vector.

21. The method of claim 1, wherein receiving one or more CSI-RS comprises receiving the one or more CSI-RS based on one or more CSI-RS ports belonging to a first number of layers.

22. The method of claim 21, further comprising: For each of the first number of layers, receiving an indication for a second number of SD beamforming components included in the respective layer, wherein receiving an indication for a restricted set includes receiving a first corresponding restricted set for each of the second number of SD beamforming components in each of the first number of layers.

23. The method of claim 21, further comprising: For each of the first number of layers, a first corresponding restricted set is received.

24. The method of claim 21, further comprising: Receive a first restricted set of the first number of layers, wherein the first restricted set is a restricted set of the FD beamforming components.

25. The method of claim 1, wherein receiving an indication of a restricted set comprises receiving an index set of the restricted set for a plurality of CSI-RS ports, wherein each CSI-RS port corresponds to an FD beamforming component having a corresponding index of the index set.

26. An apparatus comprising: Transceiver, the transceiver being configured to: The user equipment (UE) receives an indication of the restricted set of frequency domain FD beamforming components from the base station (BS). The UE receives one or more Channel State Information Reference Signals (CSI-RS) from the BS; as well as The UE transmits a Channel State Information (CSI) report indicating multiple precoding coefficients to the BS based on one or more received CSI-RS and a limited set of the FD beamforming components.

27. The apparatus of claim 26, further comprising: Processor, the processor being configured to: The UE selects one or more FD beamforming components for each spatial domain SD beamforming component based on the indication; as well as For each selected FD beamforming component, the coefficients of the plurality of precoded coefficients are determined.

28. The apparatus of claim 26, further comprising: Processor, the processor being configured to: The UE selects one or more spatial frequency beamshaped CSI-RS ports based on the indication; as well as For each selected spatial frequency beamforming CSI-RS port, determine the coefficients of the plurality of precoding coefficients. The transceiver is configured to receive one or more CSI-RS via one or more spatial frequency beamshaped CSI-RS ports at the BS.

29. The apparatus of claim 28, wherein the transceiver is configured to: The UE receives from the BS a CSI report configuration message indicating that the CSI report is based on a port selection codebook with spatial frequency beamforming.

30. The device of claim 28, wherein the processor is configured to: The UE determines the non-FD beamforming channel response matrix based on the received one or more CSI-RS and the indication; The coefficients are determined based on the non-FD beamforming channel response matrix; as well as The one or more spatial frequency beamshaped CSI-RS ports are selected based on the magnitude of the coefficients.

31. The device of claim 28, wherein the processor is configured to: The UE determines the channel estimation result for the one or more spatial frequency beamforming CSI-RS ports based on the received one or more CSI-RS and the indication; The coefficients are determined based on the channel estimation results; as well as The one or more spatial frequency beamshaped CSI-RS ports are selected based on the magnitude of the coefficients.

32. The apparatus of claim 26, wherein the transceiver is configured to: The instruction is received via Radio Resource Control (RRC) signaling messages, MAC Control Element (MAC CE), or in Downlink Control Information (DCI).

33. The apparatus of claim 26, wherein the transceiver is configured to: Receive indication of one or more discrete indices for FD beamforming components, wherein the one or more discrete indices correspond to a restricted set of the FD beamforming components.

34. The device of claim 33, wherein the one or more discrete indices include a coherent index of the FD beamforming components.

35. The device of claim 33, wherein the one or more discrete indices include the non-coherent indices of the FD beamforming components.

36. The apparatus of claim 33, wherein the transceiver is configured to: Indications to one or more discrete indices are received by receiving a bitmap, wherein each bit in the bitmap having a first value corresponds to an index included in the one or more discrete indices, and each bit in the bitmap having a second value corresponds to an index not included in the one or more discrete indices.

37. The device of claim 36, wherein the bitmap has a length of N bits, where N represents the number of subbands included in the plurality of FD beamforming components or the number of FD beamforming components, and the restricted set is a subset of the plurality of FD beamforming components.

38. The apparatus of claim 26, wherein the transceiver is configured to: Receive an indication of an index window including a start index and an end index, wherein the index window spans multiple coherent indices of the FD beamforming component and the index window corresponds to a restricted set of the FD beamforming component.

39. The apparatus of claim 26, wherein the transceiver is configured to: Receive an indication of an index window including a start index and a length value, wherein the index window spans multiple non-contiguous indices of the FD beamforming component and the index window corresponds to a restricted set of the FD beamforming component.

40. The device of claim 26, wherein the constrained FD beamforming component comprises a Discrete Fourier Transform (DFT) vector or a Discrete Cosine Transform (DCT) vector.

41. The apparatus of claim 26, wherein the transceiver is configured to: To receive one or more CSI-RS based on one or more CSI-RS ports belonging to the first number of layers.

42. The apparatus of claim 41, wherein the transceiver is configured to: For each of the first number of layers, an indication is received of a second number of SD beamforming components included in the corresponding layer; and Receive a first corresponding restricted set for each of the second number of SD beamforming components in each of the first number of layers.

43. The apparatus of claim 41, wherein the transceiver is configured to: For each of the first number of layers, a first corresponding restricted set is received.

44. The apparatus of claim 41, wherein the transceiver is configured to: Receive a first constrained set of the first number of layers, wherein the first constrained set includes the constrained set of the FD beamforming components.

45. A computer-readable medium having program code recorded thereon, the program code comprising: Code used to enable the user equipment (UE) to receive from the base station (BS) an indication of a restricted set of frequency domain FD beamforming components; Code used to enable the UE to receive one or more Channel State Information Reference Signals (CSI-RS) from the BS; as well as Code used to enable the UE to transmit a Channel State Information (CSI) report indicating multiple precoding coefficients to the BS based on a limited set of one or more received CSI-RS and the FD beamforming components.

46. ​​The computer-readable medium of claim 45, wherein the program code further comprises: Code used to enable the UE to select one or more FD beamforming components for each spatial domain SD beamforming component based on the indication; as well as Code used to enable the UE to determine the coefficients of the plurality of precoded coefficients for each selected FD beamforming component.

47. The computer-readable medium of claim 45, wherein the program code further comprises: Code for enabling the UE to select one or more spatial frequency beamforming CSI-RS ports based on the indication, wherein code for enabling the UE to receive one or more CSI-RS includes code for enabling the UE to receive the one or more CSI-RS based on one or more spatial frequency beamforming CSI-RS ports at the BS; as well as Code used to enable the UE to determine the coefficients of the plurality of precoded coefficients for each selected spatial frequency beamforming CSI-RS port.

48. The computer-readable medium of claim 47, wherein the program code further comprises: Code used to enable the UE to determine a non-FD beamforming channel response matrix based on the received one or more CSI-RS and the indication; The code used to enable the UE to determine the coefficients includes code used to enable the UE to determine the coefficients based on the non-FD beamforming channel response matrix, and The code for enabling the UE to select one or more spatial frequency beamforming CSI-RS ports includes code for enabling the UE to select the one or more spatial frequency beamforming CSI-RS ports based on the amplitude of the coefficient.

49. The computer-readable medium of claim 47, wherein the program code further comprises: Code for enabling the UE to determine channel estimation results for the one or more spatial frequency beamforming CSI-RS ports based on the received one or more CSI-RS and the indication; The code used to enable the UE to determine the coefficients includes code used to enable the UE to determine the coefficients based on the channel estimation results, and The code for enabling the UE to select one or more spatial frequency beamforming CSI-RS ports includes code for enabling the UE to select the one or more spatial frequency beamforming CSI-RS ports based on the amplitude of the coefficient.

50. The computer-readable medium of claim 45, wherein the code for causing the UE to receive an indication of a restricted set comprises code for causing the UE to receive an indication of one or more discrete indices of an FD beamforming component, wherein the one or more discrete indices correspond to a restricted set of the FD beamforming component.

51. The computer-readable medium of claim 50, wherein the one or more discrete indices comprise coherent or non-coherent indices of the FD beamforming components.

52. The computer-readable medium of claim 45, wherein the code for causing the UE to receive an indication of a restricted set comprises code for causing the UE to receive an indication of an index window including a start index and an end index, wherein the index window spans a plurality of coherent indices of the FD beamforming component, and the index window corresponds to a restricted set of the FD beamforming component.

53. The computer-readable medium of claim 45, wherein the code for causing the UE to receive one or more CSI-RS includes code for causing the UE to receive the one or more CSI-RS based on one or more CSI-RS ports belonging to a first number of layers.

54. The computer-readable medium of claim 53, wherein the program code further comprises: Code for enabling the UE to receive, for each of the first number of layers, an indication of a second number of SD beamforming components included in the corresponding layer. The code for enabling the UE to receive an indication of a restricted set includes code for enabling the UE to receive a first corresponding restricted set for each of the second number of SD beamforming components in each of the first number of layers.

55. The computer-readable medium of claim 53, wherein the program code further comprises: This is used to enable the UE to receive a first corresponding restricted set of codes for each of the first number of layers.

56. The computer-readable medium of claim 53, wherein the program code further comprises: Code for enabling the UE to receive the first restricted set of the first number of layers, wherein the first restricted set is the restricted set of the FD beamforming components.

57. An apparatus comprising: A means for receiving from a base station (BS) an indication of a restricted set of frequency domain FD beamforming components; A means for receiving one or more Channel State Information Reference Signals (CSI-RS) from the BS; as well as A means for transmitting a channel state information CSI report indicating multiple precoding coefficients to the BS based on a limited set of one or more received CSI-RS and the FD beamforming components.

58. A wireless communication method, comprising: The base station (BS) transmits an indication of the restricted set of frequency domain FD beamforming components to the user equipment (UE). The BS transmits one or more Channel State Information Reference Signals (CSI-RS) to the UE; as well as The BS receives a Channel State Information (CSI) report from the UE, which indicates multiple precoding coefficients, based on one or more transmitted CSI-RS and a limited set of the FD beamforming components.

59. The method of claim 58, wherein transmitting an indication of a restricted set comprises transmitting an indication of one or more discrete indices of an FD beamforming component, wherein the one or more discrete indices correspond to a restricted set of the FD beamforming component.

60. The method of claim 59, wherein the one or more discrete indices include coherent indices of the FD beamforming components.

61. The method of claim 59, wherein the one or more discrete indices include the non-coherent indices of the FD beamforming components.

62. The method of claim 59, wherein transmitting an indication to one or more discrete indices comprises transmitting a bitmap, wherein each bit in the bitmap having a first value corresponds to an index included in the one or more discrete indices, and each bit in the bitmap having a second value corresponds to an index not included in the one or more discrete indices.

63. The method of claim 62, wherein the bitmap has a length of N bits, where N represents the number of subbands included in the plurality of FD beamforming components or the number of FD beamforming components, and the restricted set is a subset of the plurality of FD beamforming components.

64. The method of claim 59, further comprising: Transmit instructions for a first number of FD beamforming components included in the restricted set; as well as Transmit an integer less than or equal to the combined value, which represents the number of possible results for selecting the first number of indices from the instruction.

65. The method of claim 64, further comprising: The combined value is determined according to a formula, wherein the formula includes... Where N represents the magnitude of the plurality of FD beamforming components, N′ represents the first number of FD beamforming components, and 0 to Each integer in represents the result of selecting the first number of FD beamforming components from the plurality of FD beamforming components.

66. The method of claim 65, wherein the plurality of FD beamforming components comprises a set of all possible FD beamforming components in the codebook.

67. The method of claim 65, wherein the number of quantized bits is according to a second formula, wherein the second formula includes 68. The method of claim 58, wherein transmitting an indication of a restricted set comprises transmitting an indication of an index window comprising a start index and an end index, the index window spanning a plurality of coherent indices of the FD beamforming component, and the index window corresponding to a restricted set of the FD beamforming component.

69. The method of claim 68, wherein transmitting an indication to a restricted set comprises transmitting an indication to an index window comprising a start index and a length value, the index window spanning a plurality of coherent indices of the FD beamforming component, and the index window corresponding to a restricted set of the FD beamforming component.

70. The method of claim 69, wherein the indication of the restricted subset is determined according to a formula, wherein the formula includes mod(x+i-1,N), and wherein 1<=i<=y, i represents the index of the restricted set of the FD beamforming components, N represents the size of the plurality of FD beamforming components, x represents the start index, 0<=x<=N-1, y represents the length value, and 1<=y<=N.

71. The method of claim 70, wherein the plurality of FD beamforming components comprises a set of all possible FD beamforming components in the codebook.

72. The method of claim 58, wherein the constrained set of FD beamforming components comprises a Discrete Fourier Transform (DFT) vector.

73. The method of claim 72, comprising: The beamforming weights of the DFT vector are determined according to a formula, wherein the formula includes... And where N represents the number of sub-bands included in multiple FD beamforming components or the number of FD beamforming components, This represents multiple FD beamforming indices, where m represents the index of the FD beamforming component, and And the restricted set is a subset of the plurality of FD beamforming components.

74. The method of claim 73, wherein the plurality of FD beamforming indices comprises a set of all possible FD beamforming indices.

75. The method of claim 73, wherein the number of sub-bands is equal to the number of FD beamforming components.

76. The method of claim 58, wherein the constrained set of FD beamforming components comprises a Discrete Cosine Transform (DCT) vector.

77. The method of claim 76, comprising: The beamforming weights of the DCT vector are determined according to a formula, wherein the formula includes... And where N represents the number of sub-bands included in multiple FD beamforming components or the number of FD beamforming components, Let m represent multiple FD beamforming indices, m represent the index of the FD beamforming component, and m = {0, 1, ..., N-1}, wherein the restricted set is a subset of the multiple FD beamforming components.

78. The method of claim 77, wherein the plurality of FD beamforming indices comprises a set of all possible FD beamforming indices.

79. The method of claim 58, wherein transmitting one or more CSI-RS comprises using one or more CSI-RS ports belonging to a first number of layers to transmit the one or more CSI-RS.

80. The method of claim 79, further comprising: For each of the first number of layers, an indication is transmitted for a second number of spatial domain SD beamforming components included in the respective layer, wherein transmitting the indication for the restricted set includes transmitting a corresponding restricted set for each of the second number of SD beamforming components in each of the first number of layers.

81. The method of claim 79, further comprising: For each of the first number of layers, the corresponding restricted set is transmitted.

82. The method of claim 79, further comprising: Transmit a restricted set for the first number of layers.

83. The method of claim 58, wherein transmitting an indication of a restricted set comprises transmitting an index set of the restricted set for a plurality of CSI-RS ports, wherein each CSI-RS port corresponds to an FD beamforming component having a corresponding index of the index set.

84. The method of claim 58, wherein transmitting an indication to a restricted set comprises transmitting the indication via a Radio Resource Control (RRC) signaling message, a MAC Control Element (MAC CE), or in a Downlink Control Information (DCI).

85. The method of claim 58, comprising: The BS transmits a Channel State Information (CSI) report configuration message, including the indication, to the UE.

86. A wireless communication method, comprising: The base station (BS) transmits an indication to the user equipment (UE) of one or more Channel State Information Reference Signal (CSI-RS) port groups with spatial frequency beamforming. The BS transmits one or more CSI-RS signals to the UE using the one or more CSI-RS port groups; as well as The BS receives a Channel State Information (CSI) report from the UE, which indicates multiple precoding coefficients, based on one or more transmitted CSI-RS and the one or more CSI-RS port groups.

87. The method of claim 86, wherein all of the CSI-RS ports in each group correspond to a shared spatial domain SD beamforming component and a different frequency domain FD beamforming component.

88. The method of claim 86, wherein all of the CSI-RS ports in each group correspond to a shared FD beamforming component and a different SD beamforming component.

89. An apparatus comprising: Transceiver, the transceiver being configured to: The base station (BS) transmits an indication of the restricted set of frequency domain FD beamforming components to the user equipment (UE). The BS transmits one or more Channel State Information Reference Signals (CSI-RS) to the UE; as well as The BS receives a Channel State Information (CSI) report from the UE, which indicates multiple precoding coefficients, based on one or more transmitted CSI-RS and a limited set of the FD beamforming components.

90. The apparatus of claim 89, wherein the transceiver is configured to: Transmits an indication of one or more discrete indices for FD beamforming components, wherein the one or more discrete indices correspond to a restricted set of the FD beamforming components.

91. The device of claim 90, wherein the one or more discrete indices include coherent or non-coherent indices of the FD beamforming components.

92. The apparatus of claim 89, wherein the transceiver is configured to: The transmission provides an indication of an index window that includes a start index and an end index, wherein the index window spans multiple coherent indices of the FD beamforming component and corresponds to a restricted set of the FD beamforming component.

93. The apparatus of claim 89, wherein the transceiver is configured to: The transmission indicates an index window that includes a start index and a length value, wherein the index window spans multiple coherent indices of the FD beamforming component and corresponds to a restricted set of the FD beamforming component.

94. The device of claim 89, wherein the constrained FD beamforming component comprises a Discrete Fourier Transform (DFT) vector or a Discrete Cosine Transform (DCT) vector.

95. The apparatus of claim 89, wherein the transceiver is configured to: The one or more CSI-RS ports belonging to the first number of layers are used to transmit the one or more CSI-RS.

96. The apparatus of claim 95, wherein the transceiver is configured to: For each of the first number of layers, an indication is transmitted of a second number of spatial domain SD beamforming components included in the corresponding layer; and Transmit the corresponding restricted set of each of the second number of SD beamforming components in each of the first number of layers.

97. The apparatus of claim 95, wherein the transceiver is configured to: For each of the first number of layers, the corresponding restricted set is transmitted.

98. The apparatus of claim 95, wherein the transceiver is configured to: Transmit a restricted set for the first number of layers.

99. An apparatus comprising: Transceiver, the transceiver being configured to: The base station (BS) transmits an indication to the user equipment (UE) of one or more Channel State Information Reference Signal (CSI-RS) port groups with spatial frequency beamforming. The BS transmits one or more CSI-RS signals to the UE using the one or more CSI-RS port groups; as well as The BS receives a Channel State Information (CSI) report from the UE, which indicates multiple precoding coefficients, based on one or more transmitted CSI-RS and the one or more CSI-RS port groups.

100. The device of claim 99, wherein all of the CSI-RS ports in each group correspond to a shared spatial domain SD beamforming component and a different frequency domain FD beamforming component.

101. The device of claim 99, wherein all of the CSI-RS ports in each group correspond to a common FD beamforming component and a different SD beamforming component.

102. A computer-readable medium having program code recorded thereon, the program code comprising: Code used to enable the base station (BS) to transmit an indication of the restricted set of frequency domain FD beamforming components to the user equipment (UE). Code used to enable the BS to transmit one or more Channel State Information Reference Signals (CSI-RS) to the UE; as well as Code used to enable the BS to receive a Channel State Information (CSI) report indicating multiple precoding coefficients from the UE based on a limited set of one or more transmitted CSI-RS and the FD beamforming components.

103. The computer-readable medium of claim 102, wherein the code for causing the BS to transmit an indication of a restricted set to the UE includes code for causing the BS to transmit an indication of one or more discrete indices of FD beamforming components, wherein the one or more discrete indices correspond to a restricted set of the FD beamforming components.

104. The computer-readable medium of claim 103, wherein the one or more discrete indices comprise coherent or non-coherent indices of the FD beamforming components.

105. The computer-readable medium of claim 104, wherein the code for causing the BS to transmit an indication of a restricted set to the UE comprises code for causing the BS to transmit an indication of an index window including a start index and an end index, wherein the index window spans a plurality of coherent indices of the FD beamforming component, and the index window corresponds to a restricted set of the FD beamforming component.

106. The computer-readable medium of claim 104, wherein the code for causing the BS to transmit an indication of a restricted set to the UE comprises code for causing the BS to transmit an indication of an index window including a start index and a length value, wherein the index window spans a plurality of coherent indices of the FD beamforming component, and the index window corresponds to a restricted set of the FD beamforming component.

107. The computer-readable medium of claim 102, wherein the FD beamforming component in the constrained set comprises a Discrete Fourier Transform (DFT) vector or a Discrete Cosine Transform (DCT) vector.

108. The computer-readable medium of claim 102, wherein the code for causing the BS to transmit one or more CSI-RS includes the code for causing the BS to use one or more CSI-RS ports belonging to a first number of layers to transmit the one or more CSI-RS.

109. The computer-readable medium of claim 108, wherein the program code further comprises: Code for instructing the BS to transmit, for each of the first number of layers, an indication of a second number of spatial domain SD beamforming components included in the corresponding layer. The code for causing the BS to transmit an indication of a restricted set includes code for causing the BS to transmit a corresponding restricted set for each of the second number of SD beamforming components in each of the first number of layers.

110. The computer-readable medium of claim 108, wherein the program code further comprises: This is used to enable the BS to transmit the corresponding restricted set of code for each of the first number of layers.

111. The computer-readable medium of claim 108, wherein the program code further comprises: This is used to enable the BS to transmit a restricted set of code for the first number of layers.

112. A computer-readable medium having program code recorded thereon, the program code comprising: Code used to enable the base station (BS) to transmit to the user equipment (UE) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups with spatial frequency beamforming. Code used to enable the BS to transmit one or more CSI-RS to the UE using the one or more CSI-RS port groups; as well as Code used to enable the BS to receive a Channel State Information (CSI) report indicating multiple precoding coefficients from the UE based on one or more transmitted CSI-RS and the one or more CSI-RS port groups.

113. The computer-readable medium of claim 112, wherein all of the CSI-RS ports in each group correspond to a common spatial domain SD beamforming component and a different frequency domain FD beamforming component.

114. The computer-readable medium of claim 112, wherein all of the CSI-RS ports in each group correspond to a common FD beamforming component and a different SD beamforming component.

115. An apparatus comprising: A means for transmitting to a user equipment (UE) an indication of a restricted set of frequency domain FD beamforming components; A means for transmitting one or more Channel State Information Reference Signals (CSI-RS) to the UE; as well as A means for receiving, from the UE, a channel state information CSI report indicating multiple precoding coefficients based on a limited set of one or more transmitted CSI-RS and the FD beamforming components.

116. An apparatus comprising: A means for transmitting to a user equipment (UE) an indication of one or more Channel State Information Reference Signal (CSI-RS) port groups having spatial frequency beamforming. A means for transmitting one or more CSI-RS to the UE using the one or more CSI-RS port groups; as well as A means for receiving, from the UE, a Channel State Information (CSI) report indicating multiple precoding coefficients based on one or more transmitted CSI-RS and said one or more CSI-RS port groups.

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